Thanks; yes, that worked. I copied 2 PQ files in the way you suggested and it was no problem. I think I'd only tried using GPX files extracted from GSAK, and there's obviously something about them that the Etrex doesn't like. Odd.
Perhaps this will help you:
Try to export gpx from gsak using "%code" in "waypoint name" (inside options from export GPX). Probably you are using "%smart" option, which was great for old etrex, but useless with this new version.
Good luck !!