Alexandar, you should use the db2 utility db2adutl, to query and delete
database backups on ADSM.  DB2 uses unique object names when it sends data
to ADSM, so there is always one active object on ADSM that ADSM will never
expire.  The way to expire the object is when you use the db2adutl utility
which allows you to delete specific backups, or backups xx days old.  When
you delete a backup with db2adutl, db2adutl sends a delete-api call to
adsm for the objects.  ADSM changes the status of the objects from active to
inactive, and then the next time file expiration processing occurs the
objects are deleted from the ADSM database.

The adsmqry command is no longer used/supported?? with DB2...use db2adutl.
thanks, Cyndie Behrens (IBM San Jose)