We have a page that has some tips for running CSS HTML Validator on Mac OS X or Linux (or similar non-Windows system):
CSS HTML Validator on a Mac or Linux
Today I tried using Wine on a MacBook running OS X Mountain Lion. Wine is a compatibility layer capable of running Windows applications on several POSIX-compliant operating systems, such as Linux, Mac OS X, & BSD. Here is a good link that explains how to install it:
Installing Wine on Mac OS X
More:
https://appdb.winehq.org/objectManager. ... &iId=27614
If you're running CSS HTML Validator using Wine, then please let us know!

The above is a screenshot of CSE HTML Validator Pro v12 running on Mac OX X 10.8 (Mountain Lion) under Wine. Click it to see a larger view.