Notes/Domino 4 and 5 Forum

Hey guys, the event log give us this following problem:
05/10/2004 11:23:41 Error full text indexing document NT00000C26 in database D:\Lotus\Domino\Data\AMS.ft: Realtime service cannot locate the corresponding record in the external system
05/10/2004 11:23:41 Error full text indexing AMS.nsf: Bad document ID/key

So we cant index this database, how can we solve it???
Help please.
Thanks,
Adriana