ok sorry i couldnt help it seems a wierd one,one thing i'm unclear is you say you restored a backup,what did you restore exactly?

No, i didnt restore a backup. I just "restored" the index.php file which i had copied from a previous modification.
I only did that because i got an error about a line in the index.php file.
(which is strange to begin with, cause the addon didn't change anything to the index.php)

ahhhhhh try FTP your original index.php from when you first downloaded your vbulletin,the index.php you have FTP might be faulty,or it did not transfer properly,also did you make any edits to the index.php file for any hacks??

I have a bunch of addons....one might have required me to edit the index. But dont remember. i've done alot of editting :)

But it worked fine until that one addon.
No problems.

I'll see if i can dig up the original index.php and copy it over the current one again.

might pay you to go over all the hacks that you installed and see if any required index.php edits

Well..i already deinstalled alot of addons (also topxstats, if someone is clicking on the link mentioned above ;) )

I'll first update to 3.5.4.
If that doesnt work i'll upload the original index.html
If that doesnt work i'll try the reinstall ting..

Fixed.

Updating to 3.5.4 worked :P