IMAP Server Timeout Error "Mailbox Lock"

[Nick]

I use Outlook 2002 to check my IMAP account that is also periodically checked
by another computer at the same time. I keep getting an error in Outlook to
the effect that I have lost the "Mailbos Lock" on the account because it has
been left idle for too long. I have increased the "Server Timeout" from 1 to
10 minutes in Outlook but I keep getting this error message.

Is there any way to fix this problem, or at least to stop Outlook from
letting me know everytime my other device is accessing the account?

Thanks,

Nick