SQL Server :: Cannot Find Either Column "dbo" Or The User - Defined Function Or Aggregate "dbo.GetCandiateID"

I am not understanding why I am getting the following error (also mentioned in the subject line). I have written the following function in SQL Server 2005:

CREATE FUNCTION dbo.GetCandateID()
RETURNS INT
AS
BEGIN
declare @candidate_id int
SELECT @candidate_id = max(c.candidate_id) from dbo.candidates c
if(@candidate_id is null)
set @candidate_id = 1001
else
set @candidate_id = @candidate_id + 1
return @candidate_id
END

The function compiled properly. I have used the above function like below in the query:

select dbo.GetCandidateID()

I am getting the following error: Cannot find either column "dbo" or the user-defined function or aggregate "dbo.GetCandidateID", or the name is ambiguous