Problems with insert trigger and primary key
At first I thought this was due to the INSERT INTO pre_case that you are doing, not the INSERT INTO trigger. But that turned out not to be the case after more info was supplied.

Judging by the google results, this is a common error with INSTEAD OF triggers and presumably an identity column. The value for that column has not been generated when the INTEAD OF trigger fires, so it's NULL from ID. Change the column to be nullable and then see what you get in the ID column in the new table. If you have a value for it, then you are good to go. If you don't, it seems you'll need to generate it.


  (My end solution will be deployed onto SQL2000, SQL2005 and SQL2008R2 boxes, but I'm testing/developing on SQL2000)


CRAZY