Microsoft Outlook 2003 Contact Cards losing links.

Hope someone can help me out. I am Using Microsoft Outlook 2003, and the links in the Contact cards appears to have disappeared. The Funtionality is as follows:

Card A and Card B are linked.

Card A no longer has an active link to Card B.
Card B does have an active link to Card A.

My database has approximately 1000 entries, and it does not appear to be happening on all cards or links, just randomly. The database is also an open access database with approximately 16 users.

Has anyone come accross this same problem of lost links and have any ideas? Any help would be greatly appreciated, as the only Possible response I have found to date is to erase all contact links and regenerate them .

Thanks for your help!