Whenever any user tries to connect to DB2 via external DBMS like Oracle, Datastage or any other, then if he does not have permission for an external query execute, he won't be able to execute the programs.
The user needs a REMOTE access for that DB2 environment i.e. remote access for DB2V, DB2T etc). This is done by the Security administrators. They need to grant the access to DB2 files.
Which DB2 files? - I'll post on Tuesday. I donn know as of npw