You can avoid the timeout error message "Your IMAP server has closed the connection. This may occur if you have left the connection idle for too long" by changing the setting. The default install of Outlook 2003 provides the following configuration.
To adjust the Server timeouts setting:
From the Tools menu, select E-mail Accounts...
Select View or change existing e-mail accounts and click Next.
Select the e-mail you want to modify and click Change.
To bring up the Internet E-Mail Settings window, click More Settings...
Select the Advanced tab.
Left click on the slide-point and drag to the far right side (10 minutes). By changing the setting, you can avoid the above error message.
Click Apply and then OK.