some plugins give blank pages after moving to new server
 

Hi,
My old server died, so I uploaded a backup of my site to the new server I got.
Difference in the servers: old PHP and MySQL version 4.x new one PHP 5.1.6 and MySQL 5.0.45. Apache on the new server is 2.2.3
I adjusted the serverpaths, which had a minor difference.
vBulletin itself runs fine, but Photoplog and vBaLinks produce blank pages. IE shows header and body tags (I think IE fakes them), but FF shows nothing at all as both say the filesize is 0 kB
The site as it was restored on the new server ran smooth for a long time.

It doesn't like a buggy restore, since I have the same problem on two sites which are more or less the same in configuration: vBulletin with CMPS, vbSEO (disabled on one site now), vBaLinks and Photoplog.

So, does anyone have a clue what is wrong here?
Or does anyone have suggestions I can try?