SBS 2011 system state backup fails with "The parameter is incorrect."

Hello,

SBS 2011 System State Backup using Wbadmin fails with below error:
"The parameter is incorrect."

Below error event obseved on server:
Log Name:      Application
Source:        MSExchangeIS
Date:          11/3/2012 10:41:43 AM
Event ID:      9782
Task Category: Exchange VSS Writer
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      BENCHMARKSERVER.benchmarkcomp.local
Description:
Exchange VSS Writer (instance 63bb2fa9-885f-4d2b-81a1-69319306616b:6) has completed the backup of database 'Mailbox Database' with errors. The backup did not complete successfully, and no log files were truncated for this database.

Log Name:      Application
Source:        Microsoft-Windows-Backup
Date:          11/3/2012 10:41:46 AM
Event ID:      517
Task Category: None
Level:         Error
Keywords:      
User:          SYSTEM
Computer:      BENCHMARKSERVER.benchmarkcomp.local
Description:
The backup operation that started at '?2012?-?11?-?03T14:39:17.772401200Z' has failed with following error code '2155347997' (The operation ended before completion.). Please review the event details for a solution, and then rerun the backup operation once the issue is resolved.

Action Taken:
- Updated Exchange 2010 with latest updates.
- As per the article http://blogs.technet.com/b/askcore/archive/2010/06/18/ps-script-for-blog-enumeration-of-the-files-failed.aspx
executed script. It does not report any inavild paths.