Backup issue - MS SQL server 2005

Hi All,

We are taking Full & Diff backups through SQL Agent (Jobs are scheduled).

All servers backups are running fine. But the Full & Diff backup jobs are failing for 2 servers (SERVER_INST01, SERVER_INST02).

We are not able to find root cause of the issue. Please guide/share suggestions on our backup issue.

Please find the attached diff backup TSQL script & error details given below.

Executing the query "BACKUP DATABASE [ReportServerInt] TO  DISK = N'\\\\XYZ.DOMAIN.COM\\MYCOMP\\PROD\\SERVER_INST01\\Diffrential\\ReportServerInt\\ReportServerInt_backup_201301071900.bak' WITH  DIFFERENTIAL , NOFORMAT, NOINIT,  NAME = N'ReportServerInt_backup_20130107190048', SKIP, REWIND, NOUNLOAD,  STATS = 10
" failed with the following error: "Write on "\\\\XYZ.DOMAIN.COM\\MYCOMP\\PROD\\SERVER_INST01\\Diffrential\\ReportServerInt\\ReportServerInt_backup_201301071900.bak" failed: 64(The specified network name is no longer available.)
A nonrecoverable I/O error occurred on file "\\\\XYZ.DOMAIN.COM\\MYCOMP\\PROD\\SERVER_INST01\\Diffrential\\ReportServerInt\\ReportServerInt_backup_201301071900.bak:" 64(The specified network name is no longer available.).
BACKUP DATABASE is terminating abnormally.
10 percent processed.
20 percent processed.
30 percent processed.
40 percent processed.
50 percent processed.
60 percent processed.
70 percent processed.
80 percent processed.
90 percent processed.". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly.

Executing the query "BACKUP DATABASE [USER_DB1] TO  DISK = N'\\\\XYZ.DOMAIN.COM\\MYCOMP\\PROD\\SERVER_INST02\\Diffrential\\USER_DB1\\USER_DB1_backup_201301071900.bak' WITH  DIFFERENTIAL , NOFORMAT, NOINIT,  NAME = N'USER_DB1_backup_20130107190048', SKIP, REWIND, NOUNLOAD,  STATS = 10
" failed with the following error: "Write on "\\\\XYZ.DOMAIN.COM\\MYCOMP\\PROD\\SERVER_INST02\\Diffrential\\USER_DB1\\USER_DB1_backup_201301071900.bak" failed: 121(The semaphore timeout period has expired.)
A nonrecoverable I/O error occurred on file "\\\\XYZ.DOMAIN.COM\\MYCOMP\\PROD\\SERVER_INST02\\Diffrential\\USER_DB1\\USER_DB1_backup_201301071900.bak:" 64(The specified network name is no longer available.).
BACKUP DATABASE is terminating abnormally.
10 percent processed.
20 percent processed.
30 percent processed.
40 percent processed.". Possible failure reasons: Problems with the query, "ResultSet" property not set correctly, parameters not set correctly, or connection not established correctly.
            0

Message
Executed as user: DOMAIN\USER1. ...9.00.5000.00 for 64-bit  Copyright (C) Microsoft Corp 1984-2005. All rights reserved.    
Started:  7:00:00 PM  Progress: 2013-01-07 19:00:47.69     Source: {57B2FA24-FD3C-498C-A0BE-D2EDB289FB72}      
Executing query "DECLARE @Guid UNIQUEIDENTIFIER      
EXECUTE msdb..sp".: 100% complete  End Progress  Progress: 2013-01-07 19:00:48.69    
Source: Back Up Database Task      
Executing query "EXECUTE master.dbo.xp_create_subdir N'\\XYZ.DOMAIN".: 7% complete  End Progress  Progress: 2013-01-07 19:00:48.74    
 Source: Back Up Database Task      
Executing query "EXECUTE master.dbo.xp_create_subdir N'\\XYZ.DOMAIN".: 14% complete  End Progress  Progress: 2013-01-07 19:00:48.79    
Source: Back Up Database Task      Executing query "EXECUTE master.dbo.xp_create_subdir N'\\XYZ.DOMAIN".: 21% complete  
End Progress  Progress: 2013-01-07 19:00:48.85     Source: Back Up Database Task      Executing query "EXECUTE master.dbo.xp_create...  
The package execution fa...  The step failed.

Thanks in Advance.
Diff-backup-script.txt