[Zope] IOError using Zope

[Robert Rottermann]

Hi there,
since I upgraded to Zope 2.4.1 and Python 2.1.1 I often get an IOError
The only thing to get rid of it once it started to pop up is to restart
Zope.

What could be the reason for it and where to look for a remedy?

thanks
Robert

Error Type: IOError
Error Value: [Errno 5] Input/output error

Traceback (innermost last):
  File /var/lib/zope/lib/python/ZPublisher/Publish.py, line 223, in
publish_module
  File /var/lib/zope/lib/python/ZPublisher/Publish.py, line 187, in publish
  File /var/lib/zope/lib/python/Zope/__init__.py, line 226, in
zpublisher_exception_hook
    (Object: LockableItem)
  File /var/lib/zope/lib/python/ZPublisher/Publish.py, line 171, in publish
  File /var/lib/zope/lib/python/ZPublisher/mapply.py, line 160, in mapply
    (Object: manage_performRefresh)
  File /var/lib/zope/lib/python/ZPublisher/Publish.py, line 112, in
call_object
    (Object: manage_performRefresh)
  File /var/lib/zope/lib/python/App/Product.py, line 452, in
manage_performRefresh
    (Object: LockableItem)
  File /var/lib/zope/lib/python/App/RefreshFuncs.py, line 265, in
performFullRefresh
  File /var/lib/zope/lib/python/App/RefreshFuncs.py, line 258, in
performSafeRefresh
  File /var/lib/zope/lib/python/App/RefreshFuncs.py, line 212, in
logBadRefresh
  File /var/lib/zope/lib/python/zLOG.py, line 213, in LOG
  File /var/lib/zope/lib/python/ZLogger/ZLogger.py, line 17, in log_write
  File /var/lib/zope/lib/python/ZLogger/stupidFileLogger.py, line 99, in
__call__
  File /var/lib/zope/lib/python/ZLogger/stupidFileLogger.py, line 151, in
stupid_log_write
IOError: (see above)