>>Post the result of this query

>> SELECT @@Version,
>>	SERVERPROPERTY('Edition') AS Edition,
>>	SERVERPROPERTY('ProductVersion') AS ProductVersion,
>>	SERVERPROPERTY('ProductLevel') AS ProductLevel

>>
>>If you're using version other than Express, go to Tools Menu in SSMS, SQL Server Profiler. Run the trace right before testing your procedure. Don't forget to pause/stop trace once done using the pause/stop buttons in the Run Trace dialog.
>
>Version: 2008R2
>Edition: Standard
>ProdVers: 10.50.1600.1
>Level: RTM

Apply Service Pack 2 for your version. With SQL Server it is always a good idea to stay current with SPs.

Since you're using a standard edition, you can use SQL Profiler to see what exactly you're doing with your calls.