"A device description was missing the file extension e.g. CGM (*.cgm)"

Either replace the default Gsharprc.gsl file in the base directory of your installation with this one on ftp.avs.com/pub/uniras/distrib/7v2/base/Gsharprc.gsl.

Or if you have already altered the $UNIDIR/base/Gsharprc.gsl file then you need to replace the line that looks like this:

    define_device("php7475a", "HP 7475 Penplotter A",7,,,,"gsharp.plt (*.plt)","lpr");

    define_device("php7475a", "HP 7475 Penplotter A  (*.plt)",7,,,,"gsharp.plt","lpr");