Crystal Reports 2011 - Command object as dynamic Param - 64bit

We are using Crystal reports 2011 with SQL Server 2008 R2. We are trying to use dynamic parameters and using command object to populate the dynamic pick list.

The dynamic picklist is not populating and showing just a empty textbox while running on 64bit. I tried to run the profiler and there is no db command executed for the command object.

If I use a view instead of command object for populating the parameter - then it works. If I set the IIS to have 'Enable 32 bit application' to true, then even the command object works works. Is this a problem with choosing the correct driver? If so how do I do that?

Any ideas/help?

Thanks

Shankar.