diff --git a/lib/json-schema/attributes/formats/date.rb b/lib/json-schema/attributes/formats/date.rb
index 24b21700..451f6ff1 100644
--- a/lib/json-schema/attributes/formats/date.rb
+++ b/lib/json-schema/attributes/formats/date.rb
@@ -11,7 +11,8 @@ def self.validate(current_schema, data, fragments, processor, validator, options
           if REGEXP.match(data)
             begin
               Date.parse(data)
-            rescue Exception
+            rescue ArgumentError => e
+              raise e unless e.message == 'invalid date'
               validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors])
             end
           else
diff --git a/lib/json-schema/attributes/formats/date_time.rb b/lib/json-schema/attributes/formats/date_time.rb
index b1baa15c..01987485 100644
--- a/lib/json-schema/attributes/formats/date_time.rb
+++ b/lib/json-schema/attributes/formats/date_time.rb
@@ -14,18 +14,16 @@ def self.validate(current_schema, data, fragments, processor, validator, options
 
             begin
               Date.parse(parts[0])
-            rescue Exception
+            rescue ArgumentError => e
+              raise e unless e.message == 'invalid date'
               validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors])
               return
             end
 
-            begin
-              validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors]) and return if m[1].to_i > 23
-              validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors]) and return if m[2].to_i > 59
-              validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors]) and return if m[3].to_i > 59
-            rescue Exception
-              validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors])
-            end
+            validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors]) and return if m.length < 4
+            validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors]) and return if m[1].to_i > 23
+            validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors]) and return if m[2].to_i > 59
+            validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors]) and return if m[3].to_i > 59
           else
             validation_error(processor, error_message, fragments, current_schema, self, options[:record_errors])
           end
diff --git a/lib/json-schema/attributes/not.rb b/lib/json-schema/attributes/not.rb
index 52729ef3..64fbd6e3 100644
--- a/lib/json-schema/attributes/not.rb
+++ b/lib/json-schema/attributes/not.rb
@@ -17,7 +17,7 @@ def self.validate(current_schema, data, fragments, processor, validator, options
             message = "The property '#{build_fragment(fragments)}' of type #{data.class} matched the disallowed schema"
             failed = false
           end
-        rescue
+        rescue ValidationError
           # Yay, we failed validation.
         end
 
diff --git a/lib/json-schema/errors/json_load_error.rb b/lib/json-schema/errors/json_load_error.rb
new file mode 100644
index 00000000..f5a74b78
--- /dev/null
+++ b/lib/json-schema/errors/json_load_error.rb
@@ -0,0 +1,6 @@
+module JSON
+  class Schema
+    class JsonLoadError < StandardError
+    end
+  end
+end
diff --git a/lib/json-schema/errors/schema_parse_error.rb b/lib/json-schema/errors/schema_parse_error.rb
new file mode 100644
index 00000000..39d7cade
--- /dev/null
+++ b/lib/json-schema/errors/schema_parse_error.rb
@@ -0,0 +1,6 @@
+module JSON
+  class Schema
+    class SchemaParseError < StandardError
+    end
+  end
+end
diff --git a/lib/json-schema/util/uri.rb b/lib/json-schema/util/uri.rb
index eca9e6ed..93ed3b05 100644
--- a/lib/json-schema/util/uri.rb
+++ b/lib/json-schema/util/uri.rb
@@ -1,6 +1,8 @@
 module JSON
   module Util
     module URI
+      SUPPORTED_PROTOCOLS = Addressable::URI::PORT_MAPPING.keys.freeze
+
       def self.normalized_uri(uri)
         uri = Addressable::URI.parse(uri) unless uri.is_a?(Addressable::URI)
         # Check for absolute path
diff --git a/lib/json-schema/validator.rb b/lib/json-schema/validator.rb
index c20971b7..5a462ab9 100644
--- a/lib/json-schema/validator.rb
+++ b/lib/json-schema/validator.rb
@@ -9,6 +9,8 @@
 
 require 'json-schema/schema/reader'
 require 'json-schema/errors/schema_error'
+require 'json-schema/errors/schema_parse_error'
+require 'json-schema/errors/json_load_error'
 require 'json-schema/errors/json_parse_error'
 
 module JSON
@@ -54,17 +56,13 @@ def initialize(schema_data, data, opts={})
 
       # validate the schema, if requested
       if @options[:validate_schema]
-        begin
-          if @base_schema.schema["$schema"]
-            base_validator = JSON::Validator.validator_for_name(@base_schema.schema["$schema"])
-          end
-          metaschema = base_validator ? base_validator.metaschema : validator.metaschema
-          # Don't clear the cache during metaschema validation!
-          meta_validator = JSON::Validator.new(metaschema, @base_schema.schema, {:clear_cache => false})
-          meta_validator.validate
-        rescue JSON::Schema::ValidationError, JSON::Schema::SchemaError
-          raise $!
+        if @base_schema.schema["$schema"]
+          base_validator = JSON::Validator.validator_for_name(@base_schema.schema["$schema"])
         end
+        metaschema = base_validator ? base_validator.metaschema : validator.metaschema
+        # Don't clear the cache during metaschema validation!
+        meta_validator = JSON::Validator.new(metaschema, @base_schema.schema, {:clear_cache => false})
+        meta_validator.validate
       end
 
       # If the :fragment option is set, try and validate against the fragment
@@ -520,7 +518,7 @@ def initialize_schema(schema)
             schema = schema.to_array_schema
           end
           Validator.add_schema(schema)
-        rescue
+        rescue JSON::ParserError
           # Build a uri for it
           schema_uri = Util::URI.normalized_uri(schema)
           if !self.class.schema_loaded?(schema_uri)
@@ -551,7 +549,7 @@ def initialize_schema(schema)
         end
         Validator.add_schema(schema)
       else
-        raise "Invalid schema - must be either a string or a hash"
+        raise SchemaParseError, "Invalid schema - must be either a string or a hash"
       end
 
       schema
@@ -567,12 +565,12 @@ def initialize_data(data)
         elsif data.is_a?(String)
           begin
             data = JSON::Validator.parse(data)
-          rescue
+          rescue JSON::ParserError
             begin
               json_uri = Util::URI.normalized_uri(data)
               data = JSON::Validator.parse(custom_open(json_uri))
-            rescue
-              # Silently discard the error - the data will not change
+            rescue Schema::JsonLoadError
+              # Silently discard the error - use the data as-is
             end
           end
         end
@@ -582,10 +580,18 @@ def initialize_data(data)
 
     def custom_open(uri)
       uri = Util::URI.normalized_uri(uri) if uri.is_a?(String)
-      if uri.absolute? && uri.scheme != 'file'
-        open(uri.to_s).read
+      if uri.absolute? && Util::URI::SUPPORTED_PROTOCOLS.include?(uri.scheme)
+        begin
+          open(uri.to_s).read
+        rescue OpenURI::HTTPError, Timeout::Error => e
+          raise Schema::JsonLoadError, e.message
+        end
       else
-        File.read(Addressable::URI.unescape(uri.path))
+        begin
+          File.read(Addressable::URI.unescape(uri.path))
+        rescue SystemCallError => e
+          raise Schema::JsonLoadError, e.message
+        end
       end
     end
   end
diff --git a/test/test_initialize_data.rb b/test/test_initialize_data.rb
index bf61c65f..db29a6a3 100644
--- a/test/test_initialize_data.rb
+++ b/test/test_initialize_data.rb
@@ -14,7 +14,7 @@ def test_parse_character_string
       JSON::Validator.validate(schema, data, :json => true)
     end
 
-    assert_raises(Errno::ENOENT) { JSON::Validator.validate(schema, data, :uri => true) }
+    assert_raises(JSON::Schema::JsonLoadError) { JSON::Validator.validate(schema, data, :uri => true) }
   end
 
   def test_parse_integer_string
@@ -27,7 +27,7 @@ def test_parse_integer_string
 
     assert(JSON::Validator.validate(schema, data, :json => true))
 
-    assert_raises(Errno::ENOENT) { JSON::Validator.validate(schema, data, :uri => true) }
+    assert_raises(JSON::Schema::JsonLoadError) { JSON::Validator.validate(schema, data, :uri => true) }
   end
 
   def test_parse_hash_string
@@ -40,7 +40,7 @@ def test_parse_hash_string
 
     assert(JSON::Validator.validate(schema, data, :json => true))
 
-    assert_raises(Errno::ENOENT) { JSON::Validator.validate(schema, data, :uri => true) }
+    assert_raises(JSON::Schema::JsonLoadError) { JSON::Validator.validate(schema, data, :uri => true) }
   end
 
   def test_parse_json_string
@@ -53,7 +53,7 @@ def test_parse_json_string
 
     assert(JSON::Validator.validate(schema, data, :json => true))
 
-    assert_raises(Errno::ENOENT) { JSON::Validator.validate(schema, data, :uri => true) }
+    assert_raises(JSON::Schema::JsonLoadError) { JSON::Validator.validate(schema, data, :uri => true) }
   end
 
   def test_parse_valid_uri_string
@@ -83,11 +83,17 @@ def test_parse_invalid_uri_string
 
     assert(JSON::Validator.validate(schema, data, :parse_data => false))
 
+    stub_request(:get, "foo.bar").to_return(:status => [500, "Internal Server Error"])
+
+    assert(JSON::Validator.validate(schema, data))
+
+    assert(JSON::Validator.validate(schema, data, :parse_data => false))
+
     assert_raises(parser_error) do
       JSON::Validator.validate(schema, data, :json => true)
     end
 
-    assert_raises(Timeout::Error) { JSON::Validator.validate(schema, data, :uri => true) }
+    assert_raises(JSON::Schema::JsonLoadError) { JSON::Validator.validate(schema, data, :uri => true) }
   end
 
   def test_parse_integer