[dba-SQLServer] Invalid Object Name in Function

Team,

I Have SQL2008 R2.

The following function which is saved in the SQL database has the 
function name underlined in red with the error Invalid Object 
name.  Does anyone know what the problem might be?

It seems to be saved in the database under Scalar-valued functions 
but I can't get rid of the error.

USE [iMIS10_MP]
GO
/****** Object:  UserDefinedFunction 
[dbo].[fn_MobilFuelGetNextSEQN]    Script Date: 03/05/2012 13:01:01 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:              David Emerson, Dalyn Software
-- Created:             5/3/2012
-- =============================================
ALTER FUNCTION [dbo].[fn_MobilFuelGetNextSEQN]               <- Error 
Invalid object name
(
)
RETURNS int
AS
BEGIN

         DECLARE @Result int, @NewSeqn int

         EXEC @Result=dbo.sp_iboGetCounter 'Activity',1, at NewSeqn output

         RETURN @NewSeqn

END

Regards

David Emerson
Dalyn Software Ltd
Wellington, New Zealand