Brad,
AFAIK starting Excel by automation, as you are, does not load addins
automatically. You have to load them yourself. e.g.
Application.AddIns("Analysis ToolPak").Installed = True
Using Shell, starts XL "normally" hence the addin is loaded.

NickHK

"Brad" wrote in message
ups.com...
I've only just discovered that the User Defined Function I've been
rabbiting on about is actually a function supplied by an add-in. It's
NETWORKDAYS()

Could this be something to do with the problem? Maybe I need a
reference to this Anaysis Pack addin in my Access Database???