We realized, however, that there still is a problem searching applets through the Library Browser for users that do not have access to a shell account to the server. The purpose of this followup is to point to a workaround that requires only to have "professor" permissions, and requires not server configuration.
The procedure is somewhat time-consuming, but has to be done only for a single course per WeBWorK installation. Here is a link to the file in the wiki:
Again, thanks for pointing this out and for your patience in dealing with the problem.