Outlook 2000 Contact file problem

I run Outlook 2000 through an exchange server via lan, not a modem. For whatever reason I can no longer modify any of the Contact picklist items, like any of the phone number fields etc on the front screen. I've tried Scanpst.exe on the folders on my C: drive, uninstalling and reinstalling Outlook, exporting the file and then reimporting under a new name. Nothing seems to work. I currently work around the phone field problem by including it in the address field, but there should be a better solution. Is there something I'm overlooking.