showing something in the top of the page

I am seeing this at the top of the post page when i switch to some themes.

/* */ wordpress y2008 m05 d26 h09 single s-y2008 s-m04 s-d02 s-h11 s-category-internet s-category-technology s-author-admin loggedin”>

how to hide this? I am trying different themes and it shows at the top only for some themes.

i see this when i am logged in as well as logged out but only for some themes.

browser used firefox 3
wordpress 2.5.1 (latest)
error shows in theme : k2, veryplaintxt
error not showing theme : prosense
site: meevy.com
error showing screenshot: screenshot