I have not explored Crystal Report bundled with the latest Visual Studio but using VS 2003 .NET Framework 1.1 this is how we assign a value to Report Parameter.
report.SetParameterValue("ParamName", CType(ParamValue, DateTime))
the above code assumes that your ParamValue is in Type String, kung ang ParamValue mo is in Date na you can use the code below.
report.SetParameterValue("ParamName", ParamValue)