Next step or so it asks me to put the disc in.
I suspect you're clicking on "have disk", where you should simply click on "next".
The reason XP "strangely, lists the very popular" is because it lists all the printers of major manufacturers that were available when XP was released. It would be even more strange if it managed to list those that were yet to be released...
And printing from Firefox has always been a bag of nails. You my be seeing any of several known bugs. One thing that may help is to check whether it has defined silly page margins for your printer. If you get exactly 5 pages, then that's a bug.