Crystal Reports Create Crystal Report at runtime

Message

     hi all,

i am using vb.net2008 to creating a crystal report during runtime.  i have a parametrized query ( select field1 from tablename where field1 = ? ) 

I am creating a new adodb.command and every thing is ok.
when i pass the command to crystal report  using the following 

crReport.AddADOCommand( conn, com )

i got an error:
Failed to open a rowset ... wrong number of parameters.

Thanks for help