Digital BW, The Print

I have downloaded the latest versions of QTR for windows and QTRGui,
have followed the installation instructions very carefully for my
Epson 2200 printer, but cannot get my printer to print. The
QTRLOG1.txt file,  in its last line, says : "error: unable to write
raster data to driver." The QTRLOG2.txt file, in its last line, says:
"Fatal error: PPD environment variable not set!" 

What have I done wrong and what should I do?

David Tilson