How to compare the database of a backup from another environment
It sounds to me like the used procedure is somehow suboptimal :-)
We have two easy ways to create an identical test Database from a live DB:
Simple Cloning and Snapshot Standby.
Simple Cloning is the RMAN command duplicate target database:
http://download.oracle.com/docs/cd/E11882_01/backup.112/e10642/rcmdupdb.htm#BRADV010

Snapshot Standby is even more comfortable, because you can do it very fast &amp; easy multiple times subsequently after your live DB did change:
http://uhesse.wordpress.com/2010/09/24/snapshot-standby-database-in-action/