grunt-contrib-coffee conflict?

[jfroom]

If grunt-contrib-coffee is installed in a project before node-spritesheet is, node-spritesheet fails to load. Is this user error?

⌘ npm install node-spritesheet 
npm WARN package.json [email protected] No description
npm WARN package.json [email protected] No README data
npm http GET https://registry.npmjs.org/node-spritesheet
npm http 304 https://registry.npmjs.org/node-spritesheet
npm http GET https://registry.npmjs.org/underscore
npm http GET https://registry.npmjs.org/grunt-contrib-clean
npm http GET https://registry.npmjs.org/q-fs
npm http GET https://registry.npmjs.org/async
npm http 304 https://registry.npmjs.org/underscore
npm http 304 https://registry.npmjs.org/grunt-contrib-clean
npm http 304 https://registry.npmjs.org/q-fs
npm http 304 https://registry.npmjs.org/async
npm http GET https://registry.npmjs.org/fs-boot
npm http GET https://registry.npmjs.org/rimraf
npm http GET https://registry.npmjs.org/q
npm http GET https://registry.npmjs.org/q-io
npm http 304 https://registry.npmjs.org/fs-boot
npm http 304 https://registry.npmjs.org/rimraf
npm http 304 https://registry.npmjs.org/q
npm http GET https://registry.npmjs.org/graceful-fs
npm http 304 https://registry.npmjs.org/q-io
npm http 304 https://registry.npmjs.org/graceful-fs

> [email protected] install /Users/myname/Sites/myproject/node_modules/node-spritesheet
> grunt

>> Local Npm module "grunt-contrib-coffee" not found. Is it installed?
Warning: Task "coffee" not found. Use --force to continue.

Aborted due to warnings.
npm ERR! weird error 3
npm ERR! not ok code 0

[rubenstolk]

Happens to me too!!!