Validation error

Hello!

I have validated two pages with your validator.
First: http://www.tipsandtricks.sk/css/css-design.html - this was marked as
valid
Second: http://www.tipsandtricks.sk/css/discus3.php - this was NOT marked as
valid. 
But the problem is, that there are only few differnces between that two
pages. 
The second only contains some PHP code. 
Could you help me please? Where is the mistake?



_____________________________________________________
Sincerly yours,

Andrej Mikula
http://www.tipsandtricks.sk
webmaster@tipsandtricks.sk