multiple css parse error

Hi,

I'm getting some strange validation results of this xhtml document:
http://www.man.poznan.pl/~momat/xhtml/
Although all included *.css files are separately validated successfully, the validation of the whole document (valid xhtml) produce this error message:
URI : http://www.man.poznan.pl/~momat/xhtml/css/formatting.css
Line: 0 
Parse Error - : 0 -3px; ma\rgin: 0; } #HeaderText 
URI : http://www.man.poznan.pl/~momat/xhtml/css/colors.css
Line: 0 
Parse Error - : #6495ED; } h3 
Line: 0 
Parse Error - : #FFFFFF; } #NewsLinks li:hover 
Line: 0 
Parse Error - : #434B98; } #Tabs > li 
The question is: why? All this lines seems to be correct css statements. Moreover, this two *.css files validates successfully if checked separately. Is this a bug in the validator?

Greetings,
MoMaT