#42000Incorrect number of arguments for PROCEDURE

[steve hall]

When I run the Stored Procedure from MySQLCC it works fine but when it is called from a .net it gets the error:

#42000Incorrect number of arguments for PROCEDURE XX.XX; expected x, got 0

The code in my .net would appear correct:

Dim con As New MySqlConnection(connectionString)
Dim cmd As New MySqlCommand("InsertBusiness", con)

cmd.CommandType = CommandType.StoredProcedure

[list of params here]

cmd.Parameters.Add(New MySqlParameter("?BizSubCat", MySqlDbType.VarChar, 50))
cmd.Parameters("BizSubCat").Value = Biz.BusinessSubCat

Try
con.Open()

cmd.ExecuteNonQuery()
Return CType(cmd.ExecuteScalar(), Integer)

........

Can anyone offer any suggestions?
thanks