OS X :: Convert Outlook 2003 Mail Via IMAP Fails With Full PST On Windows Box

I am converting from a Windows system to a Mac. The mail client on the Windows box is Outlook 2003. The mail on the windows box had been previously stored in a number of PST files using POP3. The recommended procedure to convert to the Mac is to first in Outlook 2003 convert from POP3 to IMAP. While in the middle of this procedure I got a message that the PST file that Outlook 2003 creates for the local IMAP store is full. Further, it is 97-2002 format file rather than the new type used as the default in Outlook 2003. In any case, I need to get the rest of the mail converted. Another issue is that viewing specific folders in the IMAP store on the Windows box results in an initial display of items, followed by the window being cleared, and the folder size function showing that the folder is empty. However, attaching to the IMAP store on the server from the Mac Mail program still shows the contents, so I think this is an anomaly of the poor implementation of IMAP in Outlook 2003. What do I need to do to get the rest of the POP3 mail into IMAP?