Hi Fairfield
First, 6 hours is 360 minutes, so DateAdd( "n", 390, Now() ) will be 6.5 hours in the future. As the server clock is only 6 hours ahead of your clock, you are looking for records that have not yet been created!
Try this:
>DateAdd( "n", 330, Now() )
Although it is more long-winded, it might be clearer to use:
>DateAdd( "n", -30, DateAdd( "h", 6, Now() ) )
--
Graham