Sass::SyntaxError: File to import not found or unreadable: compass.

If you see the error

Sass::SyntaxError: File to import not found or unreadable: compass.

while building your theme, search to find your temp folder and empty it. In the next build, the error should be gone.

But, what is this error? The building process unzips a ruby-gems.jar in the temp dir to get some scripts for the parsing of the css files. This alone is not a problem. But if you have two liferay instances in your system, and they have two different versions of this jar, this could be a problem, because the build script will try to use the version of the other liferay instance (of an old build from the other instance).

P.S. The temp directory in a linux machine is per default the "/temp". You can change it using

-Djava.io.tmpdir=/new/tmp/dir

In our case (at least in liferay 6.1) we tried to give ant this parameter but the task that does the work with ruby-gems.jar was running a new java vm and didn't pass the temp parameter to it, so this new vm was using the machines default temp directory. Perhaps somebody could change the build.xml to use a specific temp directory.