db2 restore fails (symantec net backup)

[chaitanya2487]

In veritas netbackup for DB2 on AIX, the backup was succesful and it created 4 image files.
But when restoring only one image restored successfully. Restore with all the other images failed.
error on db2 command prompt:
"SQL2025N An I/O error "515" occurred on media "VENDOR"."

Details on symantic restore activity

"1/5/2013 1:38:29 PM - Info bptm(pid=6640) INF - Waiting for mount of media id 0083L4 on server blbackup01 for reading.
1/5/2013 1:38:29 PM - requesting resource 0083L4
1/5/2013 1:38:29 PM - granted resource 0083L4
1/5/2013 1:38:29 PM - granted resource IBM.ULT3580-TD4.001
1/5/2013 1:38:31 PM - Error bpbrm(pid=6688) could not write to progress file /usr/openv/netbackup/logs/user_ops/dbext/logs/1666460.0.1357373207 on <client_target>
1/5/2013 1:38:31 PM - Error bpbrm(pid=6688) listen for client protocol error - couldn't write necessary information on /usr/openv/netbackup/logs/user_ops/dbext/logs/15585585.0.
1/5/2013 1:38:31 PM - Info bpbrm(pid=8120) child done, status 25
1/5/2013 1:38:31 PM - Info bpbrm(pid=8120) sending media manager msg: STOP RESTORE <source_client>_1357309816
1/5/2013 1:39:27 PM - Info bpbrm(pid=8120) media manager for backup id <source_client>_1357309816 exited with status 150: termination requested by administrator
1/5/2013 1:39:27 PM - Info bpbrm(pid=8120) sending media manager msg: TERMINATE
1/5/2013 2:26:27 PM - end Restore; elapsed time: 00:48:13
termination requested by administrator(150) "

The job is not manualy cancelled.

and
i changed CLIENT_READ_TIMEOUT = 1800, on client and mediaserver side.
i checked
read/
write permissions to the "/usr/openv/netbackup/logs/user_ops/dbext/
logs" directory.

connectivity is fine between client and media