Validate Backup set error

 BS Key  Type LV Size       Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ ---------------
148355  Full    23.00M     SBT_TAPE    00:01:04     27-AUG-10
        BP Key: 148357   Status: AVAILABLE  Compressed: NO  Tag: TAG20100827T143
041
        Handle: c-3389811866-20100827-02   Media: 0002L4
  Control File Included: Ckp SCN: 660768343    Ckp time: 27-AUG-10

RMAN> VALIDATE BACKUPSET 148355;

using channel ORA_SBT_TAPE_1
using channel ORA_DISK_1
channel ORA_SBT_TAPE_1: starting validation of datafile backupset
channel ORA_SBT_TAPE_1: reading from backup piece c-3389811866-20100827-02
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03009: failure of validate command on ORA_SBT_TAPE_1 channel at 08/28/2010
10:45:27
ORA-19870: error reading backup piece c-3389811866-20100827-02