USE [POLLWORKER_TRAINING]
GO
/****** Object:  StoredProcedure [dbo].[sp_Register]    Script Date: 06/17/2013 16:00:03 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER PROCEDURE [dbo].[sp_Register]
	@cosID int,
	@locid int,
	@dat int,
	@UserName varchar(50)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
declare @error varchar(max)
  SET NOCOUNT ON;

		if exists(SELECT * FROM tblTrainings WHERE Username = @UserName AND CourseID = @cosID  AND LocationID = @locid AND dateId = @dat)
begin
set @error = 'You have already signed up for this training'
raiserror(@ERROR, 12, 1)
end
		else
  DECLARE @seatsAvailable int
   SET @seatsAvailable = 0;
  SELECT @seatsAvailable =
       (select Seating_Capacity - (select count(*) from tblTrainings WHERE CourseId=@cosID )
        FROM tblLocations
        WHERE LocationId = @locID )
     
  if @seatsAvailable > 0
begin
    INSERT INTO tblTrainings (CourseId, LocationId, dateId, username) VALUES (@CosID, @LocID, @dat, @Username)
set @error = Registration is successful'
raiserror(@ERROR, 13, 1)

end
 else
begin
    INSERT INTO tblWaitingList (CourseId, LocationId, dateId, username) VALUES (@CosID, @LocID, @dat, @Username)
set @error = 'You have been placed on the waiting list. You will be immediately notified if a seat is available'
raiserror(@ERROR, 14, 1)
end
END

Thanks a lot in advance

              set @error = 'You have already signed up for this training'
              raiserror(@ERROR, 12, 1)
       end
       else
missing a BEGIN here
       DECLARE @seatsAvailable int

set @error = Registration is successful'