I have one IMAP email account and a few POP3 accounts but I never got such an error when using outlook express as my email client. After I did a search I found that Outlook was trying to periodically retrieve mail headers from the IMAP server but that's not really necessary since its a 'live' connection. The mail appears in my IMAP account when I view its Inbox folder with no need for Outlook to do automatic send/receives.
The solution is to change a setting in Outlook 2007 using the following steps:
- Navigate to Tools->Send/Receive->Send/Receive settings->Define send/receive groups or simply press the hot key Ctrl+Alt+S
- Exclude the IMAP account from any group that has a automatic send/receive scheduled (e.g. "All accounts" group)
- Navigate to Tools->Accounts..., click "Properties" for my IMAP account
- Under "General" tab, uncheck "Include this account when receiving mail or synchronizing".