[TYPO3] after upgrading to PHP 5.2.5 problems with Clearing the FE cache

[support at stonki.de]

Hello,

we are running two webserver with SuSE SLES10. Typo3 Version 4.1.1.
Today we finally upgraded them from PHP 5.1.2 to 5.2.5. Seems to work fine
except one big problem: Clearing the FE Cache results in a blank page in
left frame due to an server error:

http://www.DOMAIN.de/typo3/tce_db.php?vC=7dabcfd6ac&redirect=http%3A%2F%2Fwww.DOMAIN.de%2Ftypo3%2Falt_menu.php&cacheCmd=all

Response Header:
Date: Fri, 22 Feb 2008 07:14:22 GMT
Server: Apache
Expires: 0
Last-Modified: Fri, 22 Feb 2008 07:14:22 GMT
Cache-Control: no-cache, must-revalidate
Pragma: no-cache
Content-Length: 0
Connection: close
Content-Type: text/html

500 Internal Server Error


Any ideas what is causing this problem and how to fix it ?

Thanks
Stefan

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