Error -49 when printing

I have seen several reports (such as one from Paul Lisowski) of this -49 error (file already open with write permission), appearing with avariety of different networked (and possibly non-networked) printers, after updating to Mac OS 7.6. Usually it means that you cannot modify a file in a given application because it is already open in another application. The exact cause here appears to be unknown, but one user reported that zapping the PRAM eliminated the problem.