We received a number of items on this subject (first mentioned last time). It appears the -49 error problem is not limited just to Mac OS 7.6. As to solutions:
a. Dick Sommers found that disabling the desktop printing extensions eliminated the problem.
b. Bob Bohanek traced the problem to an interaction between these desktop printer extensions and the Virex control panel. Indeed, in a timely coincidence, yesterday's MRP notes that a new Virex 5.7.1 is out: "According to the release notes, two of the bug fixes include the resolution of problems with Disk Express and Desktop Printing which caused -49 errors."