SQL 2000 -&> SQL 2005 Nesting Error

I have sort of a weird error when attempting to create a database in SQL 2005 (migrating from SQL 2000 to SQL 2005).

I am able to run the CREATE PROC script just fine in SQL 2000, but I get this error in SQL 2005.



Msg 191, Level 15, State 1, Procedure udf_JCMS_ConcurrencyCheck, Line 2518
Some part of your SQL statement is nested too deeply. Rewrite the query or break it up into smaller queries


I can't easily past up the whole script(it's 2655 lines), but it basically takes the following form:

CREATE FUNCTION dbo.Ugly (
@PK1 int,
@PK2 int,
@PK3 int,
@TableID int,
@UpdateBy char(30),
@LastUpdate datetime ) RETURNS BIT

DECLARE @UpdatedStatus as bit
DECLARE @RecordCount as smallint

SET @RecordCount = 0
If @TabelID = 1-- Comment about TableName
BEGIN

SELECT
@RecordCount =count(UNIQUE_ID)
FROM
dbo.MyTable
WHERE
UNIQUE_ID = @PK1
ANDPROXY_ID = @PK2
ANDLTRIM(RTRIM(ISNULL(LAST_UPDATE_BY,'')))= LTRIM(RTRIM(ISNULL(@UpdatedBy,'')))
AND
(
isnull(LAST_UPDATE_DATE,'') = isnull(@UpdatedDt,'')
or
convert(datetime,convert(varchar(10),LAST_UPDATE_D ATE,101)
+ ' ' + convert(char(8), LAST_UPDATE_DATE,8)) = @UpdatedDt
)
END

If @TableID = 2 -- Comment about TableName
BEGIN
.
.
.
END

If @TableID = 3 -- Comment about TableName
BEGIN
.
.
.
END

...

If @TableID = 156 -- Comment about TableName
BEGIN
.
.
.
END


IF @RecordCount = 0
SET @UpdatedStatus = 1
ELSE
SET @UpdatedStatus = 0

RETURN @UpdatedStatus



First, THIS IS NOT MY CODE.

Second, it appears that they are trying to create a function to test if a record has been updated (I cut out a bit of that).

I don't really get why SQL 2005 throws an error here. Yes, the code is hideous and not something that I would write myself. But it's not like the function is calling itself recursively or anything.

Can anyone shed any light?

Regards,

hmscott