There are several times that you may have to restore from a production box to a beta or a QA environment as a different user. In that scenario, the restore commands will work just fine but you will receive authorization errors even when the id you used to restore has SYSADM.
Starting DB2 V9.7, SYSADM no longer has implicit DBADM privileges due to a change in security policies, You may see SQL errors like SQL0551N, SQL0552N or SQL3020N
Set the DB2_RESTORE_GRANT_ADMIN_AUTHORITIES registry variable BEFORE performing the restore. An instance bounce is required.
db2stop db2set DB2_RESTORE_GRANT_ADMIN_AUTHORITIES=ON db2set -all | grep -i db2_restore_grant [i] DB2_RESTORE_GRANT_ADMIN_AUTHORITIES=ON db2start
Once you set this variable, SECADM, DBADM, DATAACCESS, and ACCESSCTRL authorities are granted to the user that issues the restore operation.