DB2 backup failure

Hi TEam,

     We had configured new DB2 backup in our environment, it got faield with following error.

Backing up the 'GTST1' database.
Unable to backup GTST1 database due to backup request failure, SQLCODE : -2025, SQL2025N  An I/O error occurred.  Error code: "3". Media on which this error 
occurred: "VENDOR".
 .

NMDA backup failed.

64673:nsrdasv: Unable to backup GTST1 database due to backup request failure, SQLCODE : -2025, SQL2025N  An I/O error occurred.  Error code: "3". Media on which this error 
occurred: "VENDOR".
 .
--- Job Indications ---
Unable to find any full backups of the save set 'gts-db2-tst-vip.vy.no:DB2:/GTST1/NODE0000' in the media database. Recommending that a full backup be performed.

Please help on this