Spooling pages to printer doesn't spool to printer - it tries to save to a file (usually, but not always, an "*.xlr). Print spooler works just fine when not in Firefox.
Firefox on XP XP desktop, dial-up modem. "Print preview" works very well but "print" icon now results in trying to save print file to some sort of file, rather than printing. When not in FF, print routine works very well.
This anomaly is fairly recent, and I have not knowingly loaded any changes.