I wrote the following 3 lines to the file 'test.css' and let it validate per 
upload on the URL 'http://jigsaw.w3.org/css-validator/validator-upload.html':
/********************** ****************/
*.gg { color: blue; }
body { background-color: red;}

The options I made were: Warnings:all, Profile:CSS2.0, Medium:screen.

The result of the validation says: No stylesheet found.

If you remove the blank in the first line (within the comment) then the 
validator recognizes the rules.

If you write something within the comment it fails too.

But if write a blank immediately before the last asterisk in the first line 
everything works:
/********************** *************** */
*.gg { color: blue; }
body { background-color: red;}

This doesn't work:
/**********************hello****************/
*.gg { color: blue; }
body { background-color: red;}

And this works:
/**********************hello*************** */
*.gg { color: blue; }
body { background-color: red;}


Kind regards
DJ CaFe