Malformed/corrupt header causing outlook 2003 to download from POP to crash...

I have a user that has Outlook 2003 on Win XP sp1. We use ATT global net for our POP. He recieves about 150-200 spam messages a day. We use the spam feature of ATT Global net to divert a majority of the spam to what is called a "GrayMail" folder. The problem is that the graymail folder is a finite size and fills up regularly. When this happens the overflow of spam get through and downloaded with the regular email. Now the problem: Some of the spam has malformed, incomplete or currupt headers. It seems that when Outlook gets one of theses it restarts the download putting it in a loop or just plain crashes. Please let me know if I can providemore info. This is a hot one for me as it is the CEO's computer.
Another insight... When Outlook stops downloading or goes into a loop or crashes, the user has to go to his web mail and delete the offending email. Regarding the looping MS support sugested that he had his automatic send and recieve time set to to short a time and indeed he did. It was set to check every minute. I changed it to 7 minutes this should take care of the looping problem.
Hope I have provided enough clear info. Please ask me to clarify if needed. Thanks.