I found the problem. But not solution!

The backups are available as below.
RMAN> list backup of datafile 2141;


List of Backup Sets
===================

BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
55820 Incr 2 172M SBT_TAPE 00:23:06 06-NOV-07
BP Key: 55820 Status: AVAILABLE Tag: INCREMENTAL_ORACLE_BACKUP
Piece Name: bk_56419_1_637942006
List of Datafiles in backup set 55820
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
2141 0 Incr 1765344875060 06-NOV-07 /usr/local/pkg/oracle/admin/cpg/links/cpg_cf_tpts_002_07.dbf



RMAN> list backup of datafile 2142;

using target database controlfile instead of recovery catalog

List of Backup Sets
===================

BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
55820 Incr 2 166M SBT_TAPE 00:23:06 06-NOV-07
BP Key: 55820 Status: AVAILABLE Tag: INCREMENTAL_ORACLE_BACKUP
Piece Name: bk_56419_1_637942006
List of Datafiles in backup set 55820
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- --------- ----
2142 0 Incr 1765344875060 06-NOV-07 /usr/local/pkg/oracle/admin/cpg/links/cpg_ca_ipts_005_37.dbf


But before the scn of the backup of that datafile(1765344875060 ) two more datafiles were added. (datafile addition was a ever happening one in this datamart database).

SO Until scn of restore to 1765344875060 will definetely complain that other two datafiles added were not available until that scn.

I cannot offline that tablespace since that tablespace contains many datafiles.

Please let me know how to proceed.

Thanks
Venkatagiri