Parameter Problem - driving me insane

Ok here we go,

MySQL 5
MyODBC 3.51
Crystal Reports.Net
and
ASP.Net using VB.Net

Set up the connection to the DB in Crystal using MyODBC. I used the Database expert to call my Stored Procedure which has one Parameter and the code is real simple going like this:

call SuccessLetter (AppNo)

From the wizard i can see and place all the fields from the SP onto the report as long as i hard code an application number into my parameter. But as soon as i change it to a variable (as above) i get the following error from Crystal: Unknown Fields AppNo in order clause MySQL ODBC 3.51 error 42S21

On the VB code side i used
Success.SetParameterValue("AppNo", GeneralFunctions.ApplicationNo)
to set up the parameter and this does get passed thru so the error is comming from the database expert - almost as if it dont recognise that my stored procedure has a parameter. Which it does and it does work if i use the SP outside of Crystal.

Any ideas - please help me before i go bald from tearing the hair out.

ThanksAnd another weird thing i;ve noticed is that Crystal puts the stored procedure in the list of tables when i use the database expert when i go to choose my tables