Album upgrade does not work

The following information is required to get an answer:
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL (optional but very useful):
Gallery version:1.5.4-3
Apache-ssl version:1.3.34-4.1
PHP version (don't just say PHP 4, please):4.3.10-19
Graphics Toolkit:
Operating system:Debian Etch
Web browser/version (if applicable): Firefox

Hi Folks,

I just wanted to upgrade my albums but one album wont upgrade.
It contains 508 Items and the upgrade progress stops at the last Item.
It says
Upgrading item 579 of 580 . . . done.
Upgrading item 580 of 580 . . .
and stops.
If I want to open the album I get a blank page.

To troubleshoot the problem I turned on debug mode in config.php (debug is set to 2)
but i was not able to find the log file .

Has anybody experienced the same problem like me and how did you solve it
(except from deleting the album and re-adding the photos)?

Thanx in advance!