FWIW, lpr some.pdf prints correctly on this system (gs v. 8.63, and I don't have a version 7 handy right now.) The PDF was created here with that printer as the default from Konqueror.
Unless there are some single quotes missing here, you appear to be effectively doing an 'lp myPdfDocument.pdf' with the gs output going to the lp <stdin> which isn't being captured. The gs manpage says that to create an output pipe using the device setting as a filter, one would say -sOutputFile=%pipe%lpr which on my printer creates a slightly different output than the example above.
If your printer is named ljet4, then I'm not sure why you're using an -sOutputFile at all, just use -sDEVICE=lpname and skip all the pipe nonsense. If you're NOT printing to an ljet4, you need to insert the correct target device.