As Steve mentioned, C18 student version is available for free download, and AFAIK, it
should compile the USB framework. It's handy to have if you need to step-through a
C18 code example, and of course, then you can modifiy the loader for your own apps.

The ACCESS on line 1953 and line 1956 refers to access bank? Is this true? Could one find a good PIC18F4550/2550 tutorial on the web somewhere, where all about the assembler would be clearly explained?
Yes this refers to ACCESS RAM.

The best place to learn about assembler for any given PIC is in the instruction set section
of the datasheet. There are also a lot of examples on the Microchip web forum. For 18F in
general, download this: http://ww1.microchip.com/downloads/e...Doc/39500a.pdf

If you're looking for a good book on the 18F series, my favorite is Embedded Design and
the PIC18F452 Microcontroller by Peatman. This one is excellent for learning assembler
for the 18F series.