I have a Mac iBook G3 running sytem 10.4. I have a Garmin eTrex H (new last Christmas) that I just bought a PC interface cable as well as a USB to serial converter. I have downloaded Garmin's most recent Communicator Plugin for the Mac. When I log into Geocaching.com, find a cache I'm interested in, and click on "Send to GPS," it comes up, "No Devices Found." The eTrex is on, cables are all snug and fitting as they should. This is new to me and I'm about to throw the whole stupid lot into the Kennebec. I live in Richmond. Any help would be greatly appreciated.