Diagnosis
An index to a table contains a field which does not exist in the table.
The active version of the table is always used for the check. It is notsufficent that the field exists in the revised version of the table.

Procedure
Check whether you have written the field name correctly. If thismessage appears when a table is activated, check whether the field wasdeleted from the table but still exists in an index to the table.
When an index is activated directly, there is a check against theactive version of the table. If the field was newly included in thetable, the table must first be activated. The index will be activatedautomatically at that time.