These error status codes indicate corruption in a set for which the object record was being automatically connected during the MODIFY or STORE DML.
For a MODIFY, if the sortkey for a sorted set was being changed the DBMS will disconnect the record from the current set occurrence and attempt to establish currency based on the modified sortkey value so the record can be re-connected in the proper position within the set.
During a STORE, the object record is connected to all sets for which it is defined as an AUTOMATIC member.
26 minor code is "Record Not Found' so these errors indicate corruption and the ERROR SET from the IDMS STATUS display indicates the set in question.
Typically the ERROR SET is an index. Rebuilding the index using MAINTAIN INDEX should resolve the problem.
If the set is a Chain set some manual fixing of the broken chains may be necessary.
IDMSDBAN should show the set involved and the nature of the corruption in either case.