[Zope] Zope crashes on request of certain page

[Sven Jacobs]

Dear Zope list,

I have a serious problem with Zope. Every time a certain page is 
requested by a web browser for the second or third time (first time 
always works) the whole Zope server crashes :-(

The only thing special about this page are calls of external Python 
methods from a custom extension. These methods don't do any special 
magic. They just open a MySQL database (using the MySQLdb module version 
0.9.1) and return some HTML output.

I was able to catch a somewhat informative error message when Zope was 
running in debug mode:

2006-03-27T12:18:57 PANIC(300) z2 Startup exception
Traceback (innermost last):
   File /opt/zope/z2.py, line 495, in ?
     (Object: ZLogger)
   File <string>, line 1, in ?
   File /opt/zope/lib/python/Zope/__init__.py, line 37, in ?
   File /opt/zope/lib/python/ZODB/FileStorage.py, line 202, in __init__
   File /opt/zope/lib/python/ZODB/lock_file.py, line 29, in lock_file
StorageSystemError: Could not lock the database file.  There must be
another process that has opened the file.

Operating system is SuSE Linux 8.0, Zope version is 2.5.0, Python 2.2, 
MySQL 3.23.48. I know, pretty old but upgrading any of these software 
components should be avoided due to emerging costs unless absolutely 
necessary!

So if you have any idea how to fix this problem besides "upgrade to the 
newest versions" I would be glad to here from you!

Thank you very much!

-- 
Sincerely yours
Sven Jacobs