[imp] imp does not show emails

[cyx]

Hi (second try)
I have a new installation with the newest horde, imp, turba and 
kronolith versions (parallel to the old installation on another server)
Problem: some users (typically users with a lot of emails in their 
inbox) see in the title bar of IMP "1 - 20 messages out of 120" but the 
window below is empty ??
no mails are shown
Logging in with the same user in the older horde install. works fine 
and shows all the emails
If I delete all the mails (with the old imp interface) than all works 
fine with new arriving emails
Sometimes  logging in with the old imp does the trick and the mail reappears
in the new imp
Whats wrong here? Is it an IMP Problem or maybe an Courier-IMAP Problem 
or something else???
thanks for any hlep
werner

----------------------------------------------------------------
This message was sent using webmail at htlwrn.ac.at Dept. EDV.