clicking mailto: link causes many popups

I have a user running winxp pro using outlook 2003. In internet explorer, if they click on a link with a mailto: destination (ex. mailto:admin@yourdomain.com), around 70 blank popup windows appear with mailto: in the address bar. I imagine there would be more but i think the memory maxes out at around 70 windows. My hunch is that it is an email configuration problem. Has anyone experienced this and found a solution?