Frame at top in Admincp shows garbage characters
 

Hey*

for some reason* possibly after a server upgrade to php 5.2.11* there is a frame on the top of my admincp which shows garbage ASCII characters. Also when i click at certain menus on the left* i get garbage characters as a result. That happens in Firefox only. On IE* sometimes it tries to download the php file of the menu i click. I really do not know what could have caused this. I also reuploaded all the admincp files; still nothing. Can anyone help me out? Is it a server issue?

Thanks in advance