Backups failing with EC 50

Master and Media : Sun OS NBU- 7.1.0.3

Client : Win 2k8 NBU 6.5.6

Backups are failing with EC 50. I enable the multistream on the policy and found that all drives backups are completing sucessfully except for Shadow Copy Components:.

Please find the job detailed status

04/19/2013 17:16:02 - estimated 0 kbytes needed
04/19/2013 17:16:02 - Info nbjm (pid=13250) started backup job for client txalle2aformda1-ebr, policy FS_txalle2aformda1, schedule Daily_Inc on storage unit usprd248_sd_stu001_dsu_st
04/19/2013 17:16:03 - started process bpbrm (pid=8870)
04/19/2013 17:16:05 - connecting
04/19/2013 17:16:06 - connected; connect time: 0:00:00
04/19/2013 17:16:08 - Info bpbkar (pid=0) Backup started
04/19/2013 17:16:08 - Info bpbrm (pid=8870) bptm pid: 8902
04/19/2013 17:16:09 - Info bptm (pid=8902) start
04/19/2013 17:16:09 - Info bptm (pid=8902) using 1048576 data buffer size
04/19/2013 17:16:09 - Info bptm (pid=8902) using 32 data buffers
04/19/2013 17:16:12 - Info bptm (pid=8902) start backup
04/19/2013 17:16:13 - Info bptm (pid=8902) backup child process is pid 8915
04/19/2013 17:16:13 - begin writing
04/19/2013 17:49:51 - Error bpbrm (pid=8870) from client txalle2aformda1-ebr: ERR - Unable to backup System State or Shadow Copy. Please check the state of VSS and associated Writers.ERR - Unable to backup System State or Shadow Copy. Please check the state of VSS and associated Writers.INF - Estimate:-1 -1
04/19/2013 17:49:51 - Error bpbrm (pid=8870) from client txalle2aformda1-ebr: ERR - Unable to backup System State or Shadow Copy. Please check the state of VSS and associated Writers.INF - EXIT STATUS 69: invalid filelist specification
04/19/2013 17:49:51 - Warning bpbrm (pid=8870) from client txalle2aformda1-ebr: WRN - archive bits will NOT be cleared
04/19/2013 17:49:52 - Critical bpbrm (pid=8870) unexpected termination of client txalle2aformda1-ebr
04/19/2013 17:49:52 - Error bptm (pid=8915) system call failed - Connection reset by peer (at child.c.1296)
04/19/2013 17:49:53 - Error bptm (pid=8915) unable to perform read from client socket, connection may have been broken
04/19/2013 17:49:53 - Error bptm (pid=8902) media manager terminated by parent process
04/19/2013 17:50:09 - Error bpbrm (pid=8870) could not send server status message
04/19/2013 17:50:10 - Info bpbkar (pid=0) done. status: 50: client process aborted
04/19/2013 17:50:10 - end writing; write time: 0:33:57
04/19/2013 18:00:10 - Info nbjm (pid=13250) starting backup job (jobid=10841210) for client txalle2aformda1-ebr, policy FS_txalle2aformda1, schedule Daily_Inc
04/19/2013 18:00:13 - Info bpbrm (pid=21802) txalle2aformda1-ebr is the host to backup data from
04/19/2013 18:00:13 - Info bpbrm (pid=21802) reading file list from client
04/19/2013 18:00:14 - Info bpbrm (pid=21802) starting bpbkar on client
client process aborted  (50)
 

Please suggest in this regard..

Currently i don't have access on the client ...Please let me know what all settings needs to be checked on client so that i can ask the concerned team to do that..

TIA