This is almost certainly a client-side issue. The fact that it happens with qpopper as well as ipop3d indicates that the problem is independent of the server implementation.
If you are running an anti-virus program with email scanning, it could be interfering with the POP3 traffic. Another thing to look at is if there is a periodic "new mail check" or other such task that goes off at a regular interval. I have seen cases where this happens while a message is being downloaded, killing the download. -- Mark -- http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate. Si vis pacem, para bellum.
