In release 8.1.6 and higher, Oracle correctly normalizes filenames so you don't need this procedure.
In releases prior to 8.1.6, a flawed filename normalization mechanism allowed two different filenames to refer to one physical file. DBMS_BACKUP_RESTORE corrects this so that Oracle accurately identifies all physical files referenced in the control file and the recovery catalog. For more information on this package see the manual:
Oracle9i Database Migration.