heroku rake assets:precompile failed. Invalid CSS.

Today i played with sass and compass in my current rails project. On my local machine everything works fine. But when i want to make an update to my heroku app i got the following error:

Running: rake assets:precompile
rake aborted!
Invalid CSS after ” *”: expected identifier, was “/”
(in /tmp/build_3tizuffxebjqm/app/assets/

the funny thing is, [...]