nsrndmp_save: data start backup: I / O error

hi,all

  when i configure a  backup large small files with snapimage module.  it is always unsuccess.  the folloing error messags:

Retry times.
Server Debug: The process id for an NDMP the service is 4 704
42 794: nsrndmp_save: backup to a non-NDMP type of device
42658: nsrdsa_save: DSA storage time = 1337217585
Server Debug: The process id for an NDMP the service is 5 156
Host = win-rneqfoa0f3n (14.1.78.202) port = 8647
42597: nsrndmp_save: data start backup: I / O error
42886: nsrndmp_save: Unable to start the NDMP backup process.
nsrdsa_save: Aborted

42913: nsrndmp_save: successfully closed with NW server storing the session

the backup failed.
: Failed with error (s)

description of current environment:

networker version: 7.6.2

networker snapimage version:.2.5

networker client OS type:window2003R2

networker server OS type:windows2008R2.

this is non-NDMP backup

process of  configure backup

  create a networker client

on the  apps and modules tab,

   for the remot user attribute:set the value is networker client of snapimage  user name.

  for the passwod attribute:set the value is networker client of snapimage  user password

  for the backup command attribute: set the value is   nsrndmp_save -M -T image

  select yes for the NDMP attribute