Failure Running Clean Commands

[manonatelier]

I'm using TextMate version 2.0-alpha.9537 on an iMac with Mavericks 10.9.2.
This is a completely clean install of TextMate 2. There is no TextMate 1 installed on this machine.

When choosing "Clean SCSS", get this error message:

Failure running “Clean SCSS”.
Clean SCSS: line 4: sass-convert: command not found

Same error message for the following:
Clean Sass (line 4: sass-convert: command not found)
Convert Selection from Sass to SCSS (line 4: sass-convert: command not found)
Convert Selection from CSS to SCSS (line 4: sass-convert: command not found)
Convert Selection from CSS to Sass (line 4: sass-convert: command not found)
Convert Selection from SCSS to Sass (line 4: sass-convert: command not found)
Export to CSS ( line 5: sass: command not found)