Sybase backup failed with with "Sybase Message: Can't open a connection to site 'SYB_BACKUP'" (4044197)

Date - 10/2007
Affected Product & Version - NetVault: Backup 7.4.5
Affected Module & Version - APM Sybase (Version 2.407 and 2.5.13)
OS Version - Windows 2000/2003
Application Information - Sybase ASE 12.5

Description:
Sybase backup failed with with "Sybase Message: Can't open a connection to site 'SYB_BACKUP'"

Symptoms:
Sybase backup failed with with "Sybase Message: Can't open a connection to site 'SYB_BACKUP'"

From the binary log context:
Sybase Message: 'Can't open a connection to site 'SYB_BACKUP'. See the error log file in the SQL Server boot directory. '

Upon inspecting the sybase message log, you see the following:

00:00000:00025:2007/10/17 17:26:53.17 kernel Connectivity Library (Directory Control Layer) Error: Error returned by service provider.
00:00000:00025:2007/10/17 17:26:53.17 kernel Connectivity Library (Directory Control Layer) Error: (InterfacesDriver): Requested server name not found.
00:00000:00025:2007/10/17 17:26:53.17 server Error: 7220, Severity: 11, State: 1
00:00000:00025:2007/10/17 17:26:53.17 server Site 'SYB_BACKUP' not found in interfaces file.
00:00000:00025:2007/10/17 17:26:53.17 server Error: 7235, Severity: 17, State: 0

1. Make sure that the sybase backup server is running

and

2. Verify that the srvnetname for the SYB_BACKUP matches the name created for the backup server in Sybase.
From Isql
1> select * from master..syssevers
2> go

If there is a mismatch, update the name by using sp_dropserver and sp_addserver if necessary

1> sp_dropserver SYB_BACKUP
2> go

1> sp_addserver SYB_BACKUP, null, SERVERNAME_BS
2> go

*Where SERVERNAME_BS is the network name of sybase backup server