You can’t do date arithmetic like this in BO. You need to use daysbetween(), but that only has a precision of 1 day. Alternatives are
[list]Creating the difference object in the universe using native DB functions
using the DLL add-in here and using the datediff function that provides. (go here for a version 6 version ( which nobody but me has vierified yet)
Creating the objects as non-date/time and using seconds since the date X and then normal subtraction will work.
[/list]
I’m sure there are other ways maybe a search or too might help, this sort of thing is covered many times over.
ken.gaul 
(BOB member since 2002-06-18)