ENVIRONMENT/CONDITIONS:
NetBackup 6.5.0 client for Windows
10 Clients backing up to the same disk storage unit at the same time
Clients are Windows 2003 Server
Clients have the Windows Server 2003 Scalable Networking Pack installed
Clients have Hewlett-Packard NC373i Multifunction Gigabit Server Adapter

EVIDENCE:
Backing up a single client at a time is successful.  When all client backups are initiated simultaneously, some clients will exit with status 24.

From the Windows 2003 client registry:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
"EnableTCPChimney"=dword:00000001

The following is seen in the client's bpbkar log:
12:44:14.293 AM: [5420.6320] <32> TransporterRemote::write[2](): FTL - SocketWriteException: send() call failed, could not write data to the socket, possible broken connection.
...
12:44:14.309 AM: [5420.6320] <2> tar_base::V_vTarMsgW: INF - EXIT STATUS 24: socket write failed

From bpbrm log:
00:45:14.201 [11553] <2> bpbrm wait_for_child: child exit_status = 82 signal_status = 0
00:45:14.201 [11553] <2> inform_client_of_status: INF - Server status = 24
00:45:14.202 [11553] <2> put_long: (11) network write() error: Broken pipe (32); socket = 7
00:45:14.202 [11553] <16> inform_client_of_status: could not send server status message
...
00:45:18.739 [11553] <2> bpbrm Exit: client backup EXIT STATUS 24: socket write failed


SOLUTION/WORKAROUND:
Contact the hardware vendor of the NIC for the latest updates for their product as a resolution.

This problem occurs when the TCP Chimney Offload feature is enabled on the NetBackup Windows 2003 client.  Disable this feature to workaround this problem.

To do this, at a command prompt, enter the following:
 Netsh int ip set chimney DISABLED
 

REFERENCE:
 http://support.microsoft.com/kb/942861