I hardly ever use the dataadapter- I use straight up cmd objects and stored procs... but...
so that delete command you posted... I assume that is captured off a break point on myAdapter.DeleteCommand = etc ?
so my question is this... that is not a valid sql statement...
DELETE FROM [dbo].[DisplayList] WHERE (([PropertyID] = @p1) AND
([DisplayID] = @p2) AND ([DisplayName] = @p3) AND ((@p4 = 1 AND
[TerminalID] IS NULL) OR ([TerminalID] = @p5)))
it should pop an error, unless you have those values @p1,@p2, etc... if you DO have those values, have you tried running that query in SQLManagement studio?