Billy Smith wrote:
Specifically:

1. Where the back frame fits into a rabbet in the side frames, it
is screwed in but should I glue this joint too?

I never glue my back in.. The purpose of the back is to prevent the
cabinent from racking (in general).. use the recommend fasteners the
plans say, and you'll be fine.


2. The bottom frame sits in a groove at the bottom of the cabinet;
should I glue that joint all the way around?


3. The plans say nothing about joining the top frame to the side
and back frames. I could screw the top frame into the other frames
but it seems better to use biscuits and glue it on.


Since I don't know exactly what you are doing, I'm going to recommend
you just follow the plans.. My guess is that where you screw the bottom
in will not be seen. My second guess is that the solid wood top hides
the top frame.
There's nothing wrong with just using mechanical fasteners where
appropriate. Everything doesn't have to be glued in. Heck, your house
is being held together with fasteners and no glue. As the other poster
said, sometimes using glue where you shouldn't causes wood movement
problems later.
When in doubt, I'd follow the plans to the letter and not risk ruining
the project because you feel comfortable with extra glue.