I have the same problem. Wasted almost a day for troubleshooting Windows 7 and Outlook 2003 when stopped receiving mail today (POP3 with SSL). I have tested uninstall-reinstall Office, repair, reconfig Outlook, everything... As last try I have uninstalled EIS and Outlook worked again.
Receiving mail works if I disable control of SSL/TSL protocol.
Disabling protocol filtering is another solution but in that case a lot of red colors.