How to get distinct values in sharepoint List using SSRS

Hi,

I have referred a link thishttp://social.msdn.microsoft.com/Forums/en-US/sqlreportingservices/thread/6495db18-a1c1-480b-8c92-89c74ee47cf5/.

But what I faced is the parameter is coming disabled. I followed above mentioned thread and Followed Walkthrough given by Jin Chen. But still I am facing the same issue.

Before the Duplicate drop down Parameter, I have another normal drop down parameter.

Please help me to get rid of this.

Thanks in Advance,

Padhu