webmail not working, again!

[#1]

yet again, there is the problem of webmail not working, for some mailboxes. click on an item in inbox and in IE you get

Quote

Internet Explorer cannot display the webpage

in the righthand frame, in firefox the righthand frame is just blank.
last few reports of this at http://community.plus.net/forum/index.php/topic,67445.0.html and http://community.plus.net/forum/index.php/topic,66522.0.html
Every time this happens, can't read emails from my main email address, but works with a second mailbox I have set up.
Noticed there is a service status, but as usual the "next update" is running over 2 hours late (are "next updates" ever posted on time?)
Just wondering if plusnet have got to the bottom what is causing this, given that this now seems to be a monthly occurrence - yet it seems to take ages to fix each time.

[#2]

Sorry about the lack of update. Have just posted to Service Status but there's not much more information at the moment I'm afraid
If there are any more people experiencing problems then it would help if you can post examples here to assist in our investigation?
The last time this happened, we restarted apache on the Webmail servers and the problem seemed to go away. On the previous two occasions though it seemed to subside by itself.
Anyway, rest assured we're continuing to look into it but there may not be another update until tomorrow morning now.

[#3]

OK, after looking into this in more detail, we found lots of errors on webmail01 which went away when the log files rotated.
The last time we saw this it was happening on webmail03 so the problem doesn't appear to be server-specific.
A quick Google of the specifics shows that we're not alone with this particular problem, however in all instances restarting the server clears it.
All should be OK now but if this continues to cause us problems then  we may need to look into making some architectural changes.