Docpad error after Sass install

I want to start to work with foundation 4. So I installed Ruby and Sass.

After I installed Sass gem, I get the following error message on docpad generate:

error: An error occured:
Error: spawn ENOENT
    at errnoException (child_process.js:948:11)
    at Process.ChildProcess._handle.onexit (child_process.js:739:34)
    → [2013-05-31 13:23:20.812] [C:\Users\USERDIR\AppData\Roaming\npm\node_modules\docpad\out\lib\docpad.js] [DocPad.log]
error: An error occured:
Error: spawn ENOENT
    at errnoException (child_process.js:948:11)
    at Process.ChildProcess._handle.onexit (child_process.js:739:34)
    → [2013-05-31 13:23:20.820] [C:\Users\USERDIR\AppData\Roaming\npm\node_modules\docpad\out\lib\docpad.js] [DocPad.log]

I'd like to use sass for generating foundation inside docpad. I've tried to use this foundation docpad skeleton: https://github.com/axyz/zurb-foundation.docpad

What can cause this and how could I solve it?

a bit old question, however I've just updated https://github.com/axyz/zurb-foundation.docpad in order to support foundation v4.3.2 right now it seems to work well.

however I had to switch from pure sass to the nodesass implementation (keeping updated manually the source of foundation, maybe it could be switched to a git submodule). I had to switch not only for performance reason, but also because i had problems with the sass plugin: it just get stuck during docpad run whenever there is some file to parse like example.css.scss

It's likely the same as this issue - https://github.com/docpad/docpad-plugin-sass/issues/6 - that being that DocPad was unable to automatically detect your sass installation path, so you'll have to specify it manually by adding the following to your docpad configuration file

plugins:
    sass:
        sassPath: 'theValue'
        scssPath: 'theValue'
        compass: 'theValue'