Errors printing with cups
Problem
I had some odd errors when printing from firefox (linux) to a cups server to a brother MFC7820N. Whenever there was a image to print, the printer printed only this error message:ERROR NAME; configurationerror COMMAND; setpagedevice OPERAND STACK; --dicttype--
Printing to file (pdf or ps) and then printing with another program works.
Solution
Install or unpack the latest Windows driver. Search for a file called BM7820N.PPD and copy it over the /etc/cups/ppd/YourPrinterName.ppd
It seems that the GPL'd drivers are way too old!