SQL Parameters through C# won't work

Hi there, i'm new here, as you may see heh.

Anyways, i have a problem passing parameters to an SQL stored procedure.

Im still new to SQL, especially to Stored procedures and parameters, so it might be a stupid question.

This is the stored procedure:

CREATE PROCEDURE checkBooking
AS

DECLARE @ScheduleID varchar(50)
DECLARE @ScreenColumn int
DECLARE @ScreenRow int

Select * from tblBooking where BookingScheduleID = @ScheduleID AND BookingScreenRow = @ScreenRow AND BookingScreenColumn = @ScreenColumn

This is supposed to accept 3 parameters and return all the data back to the user.

When i try to input the parameters through C# i always get this error:

'Procedure checkBooking has no parameters and arguments were supplied.'

I tried it in two ways but i still get this error

This is the first attempt in C#:

            comm.CommandText = "checkBooking";
            comm.CommandType = CommandType.StoredProcedure;

            comm.Parameters.AddWithValue("@ScheduleID", selectedScheduleID);
            comm.Parameters.AddWithValue("@ScreenColumn", column);
            comm.Parameters.AddWithValue("@ScreenRow", row);

This is the second:

            comm.Parameters.Add("@ScheduleID", SqlDbType.VarChar);
            comm.Parameters[0].Value = selectedScheduleID;
            comm.Parameters[0].Direction = ParameterDirection.Input;

            comm.Parameters.Add("@ScreenColumn", SqlDbType.Int);
            comm.Parameters[1].Value = column;
            comm.Parameters[1].Direction = ParameterDirection.Input;

            comm.Parameters.Add("@ScreenRow", SqlDbType.Int);
            comm.Parameters[2].Value = row;
            comm.Parameters[2].Direction = ParameterDirection.Input;

Am i doing something wrong with the way i pass the parameters? or perhaps the sql is just wrong?

Please help, Regards and thanks.