[Zope] left frame loads after a very long time

Hi, loading the ZMI with a browser is usually a rather long process but since we updated the OS on our machine (Suse 10.1 with GCC 4.1) the left frame (manage_menu) needs now more than 4mn to be loaded eating all the cpu. We use a ZEO-configuration with Zope-2.8.7. I installed the ZopeProfiler but can't figure out much of the output. The script "ClientStorage.py" is the one that takes the longest time by far. Any clues as to what might be wrong there or where I should have a look to understand the problem more deeply? Thanks in advance for any help. Raphael