I tried to backup the SQL Server 2008 database 
using the following code: 
 

    BACKUP DATABASE [DataStore] TO  DISK ='E:\SQLServerDatabase\DataBasebackUpOct302012.bak'

and I get the following error:

> Msg 2601, Level 14, State 1, Procedure sp_flush_commit_table, Line 15
> Cannot insert duplicate key row in object 'sys.syscommittab' with
> unique index 'si_xdes_id'.
> 
> Msg 3013, Level 16, State 1, Line 1 BACKUP DATABASE is terminating
> abnormally. The statement has been terminated.
> 
> Msg 3999, Level 17, State 1, Line 1 Failed to flush the commit table
> to disk in dbid 11 due to error 2601. Check the errorlog for more
> information.

Could somebody suggest a solution to this problem?

The version is Microsoft SQL Server 2008 (RTM) - 10.0.1600.22 (X64) Jul 9 2008 14:17:44  (64-bit) on Windows NT 6.1 <X64> (Build 7600: )

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_In reply to the comments below:_

**Aaron Bertrand**,
Thank you. I am going to look into service packs and hope that is going to resolve the issue.  

**SQL-Learner**,

Never used the change tracking services before.But we had unexpected Windows Server shutdowns due to mishandling 2-3 times.

Looks like I have to apply a service pack.

**mrdenny**,

**Results after using DBCC CHECKDB** 
Errors:

    Msg 2601, Level 14, State 1, Procedure sp_flush_commit_table, Line 15
    Cannot insert duplicate key row in object 'sys.syscommittab' with unique index 'si_xdes_id'.
    The statement has been terminated.
    Msg 2601, Level 14, State 1, Procedure sp_flush_commit_table, Line 15
    Cannot insert duplicate key row in object 'sys.syscommittab' with unique index 'si_xdes_id'.
    DBCC execution completed. If DBCC printed error messages, contact your system administrator.
    Msg 3999, Level 17, State 1, Line 1
    Failed to flush the commit table to disk in dbid 11 due to error 2601. Check the errorlog for more information.
    Msg 3999, Level 17, State 1, Line 1
    Failed to flush the commit table to disk in dbid 11 due to error 2601. Check the errorlog for more information