I have a Gestetner printer, installed via CUPS and working under other pdf readers like Evince.
However, with Adobe Reader, I get an error:
lpq : Gestetner : unknown printer
lpstat -a lists the printer as accepting requests, however
lpr -P Gestetner_MP7500 yields again the
unknown printer error.
One workaround I have found is installing cupsys-bsd, which removes lpr. The only annoyance(!) is that it crashes now when I select duplex and click OK.
I am running Debian by the way.