Blank Admin Pages After Upgrade and Fresh Install

I have several wordpress blogs on the go and recently ran into this problem with two of them. After upgrade or fresh install I would get blank admin pages on some pages (write, manage, options). Turned out to be a ZEND Optimizer problem.

First time was during an upgrade from 2.2 to 2.3.2. Did not find any solution that worked on this forum. Ended up having to do a complete recovery from backup.

The second time I did a fresh install of wordpress 2.3.3 to see if this was an upgrade problem. Exact same problem.

Using phpMyAdmin I was able to see that runtime counts of aborts was going up every time I tired to reload an admin page. So I put a call into my to see if they could see something from there end.

Host company determined the problem was with their configuration of ZEND optimizer (sorry no detail on what they changed or what version they are running). The fresh install worked fine now. To see if my upgrade problem was the same thing I did a restore of the old 2.2 site and an upgrade to 2.3.3 which worked fine.

So might be worth a call into your hosting company if you have tried everything else.

Any WordPress gurus have a comment on why 2.2 seemed to be ok and 2.3.3 was not so lucky?

Hosting details:
PHP Version => 5.2.5
MySQL Version => 4.1.22-standard
System => Linux