"Directories" Preference Not Parsing Variables

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Set directory in preferences to something like "%USERPROFILE%\Documents\My 
Games\VBA\Saves"
2. Let emulator attempt to save a file.

What is the expected output? What do you see instead?
   Expectation is to have the file saved to "C:\Users\USERNAME\Documents\My Games\VBA\Saves\". The actual outcome is an error from the emulator that the file cannot be saved.

What version of the product are you using? On what operating system?
   Windows SVN421 (Oct 16 Release), though this is present in all versions, even back to the original 1.7.2 emulator download before re-recording was implemented.

Please provide any additional information below.
   This is certainly not a critical bug. In fact, beyond the error box popping up, the emulator will continue as expected, though with no save being created. I'm sure there aren't as many multi-user situations that occur, this should be a fairly simple fix that would make the situations that would occur disappear.

Original issue reported on code.google.com by dcollins215 on 3 Nov 2011 at 11:44