[Zope] Zserver stability problems

[nuno]

Hello,

I'm running zope 2.3.0 (Red -Hat Linux) behind apache with mod_proxy
(ProxyPass)  and fastcgi .
All requests are satisfied successfully  by Zserver , however it seems that
sometimes the zope listener
has to be restarted , which is not good !

What I have observed in particular, was that both apache an zope are up and
working fine!
But suddenly, all the requests made through browser to the zope web site,
become in a blank page, the browser takes a long time to load and it shows
up the not found web page.

What seems to me so strange is, when this happen, both listeners are up (
netstat -l ).
Then I do a restart to the zope listener and all becomes fine again !

During last week this happened four times !

I have read the zope.org mailing list and saw that other persons have
problems with Zope Server, but I haven't found any suitable solutions
to this problem of Zserver stability.

Do you guys have any hints about the reasons of this behaviour?
What should it cause this unexpected problem ?

Thank you all

Best regards
Nuno