Hold on .....

You don't have to give the DBA privileges to RMAN user. The privileges that you give to the rman are as follows

CONNECT, RESOURCE and RECOVERY_CATALOG_OWNER


Once after doing this,

do the following

rman catalog rman_user/pwd@rman_instance

RMAN> create catlog tablespace rman_tablespace


This would create the catalog in the database for you. The catrman.sql was some thing that we had to use in the prior versions of oracle. But as of 8i, ram is created using catproc and catalog scripts i presume (I'm not suer infact).

Once the catalog is created

RMAN> target sys@target_database


RMAN> register database;

This would register the database in your catalog and do a fully sync.

Good luck
Sam