Windows 2008 R2 will not backup system state

Im trying to backup my Windows 2008 R2's system state backup but backup always failing and event viewer showing the following event. How can I fix that issue?

 

Log Name:      Application
Source:        Microsoft-Windows-Backup
Date:          19/04/2011 6:56:33 AM
Event ID:      517
Task Category: None
Level:         Error
Keywords:      
User:          SYSTEM
Computer:      server.domain.local
Description:
The backup operation that started at '?2011?-?04?-?019T20:46:32.413528800Z' 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.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Backup" Guid="{1DB28F2E-8F80-4027-8ZZB-A11F7F10F62D}" />
    <EventID>517</EventID>
    <Version>0</Version>
    <Level>2</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8000000000000000</Keywords>
    <TimeCreated SystemTime="2011-19-04T20:56:33.139383900Z" />
    <EventRecordID>5698</EventRecordID>
    <Correlation />
    <Execution ProcessID="4308" ThreadID="4808" />
    <Channel>Application</Channel>
    <Computer>server.domain.local</Computer>
    <Security UserID="S-1-5-18" />
  </System>
  <EventData>
    <Data Name="BackupTime">2011-19-04T20:46:32.413528800Z</Data>
    <Data Name="ErrorCode">2155347997</Data>
    <Data Name="ErrorMessage">%%2155347997</Data>
  </EventData>
</Event>