Modify Table Key

I have a problem with a table where FIELD_X is being modified (it is the primary key). When I try to make the change, either in the table or in a form, I get the message: “The field below must be included in the table’s primary key.” Field: FIELD_YYY Table: THETABLE FIELD_YYY is another key to the table. Any suggestions as to where I would look to fix this problem?

You get this error if you have defined the tablerelation on a field incorrectly, that is if you refer to a field in the definition (tablerelation property) and this field is not part of the primary key in the related table (hope this makes sense). Regards Steffen Voel

Steffen, thanks very much for the tip. I was looking at the table involved but I see now that it is other related tables that have been causing the problem. I now have it working.