"An error occurred in the underlying security system" in Outlook 2

Installed a Verisign digital id yesterday and get the above message when
trying to access some sent/received e-mails during the testing process. I am
running Outlook 2003 on Windows XP Professional. We have more than one e-mail
account running within Outlook but the id has only been purchased for one
address for now. Some seem to be OK, some are not so difficult to pinpoint. I
have exported, removed and reinstalled id to no effect. Verisign gave up -
said was an Outlook problem.