Hello Paul:
First of all, very nice BB you have here, I have enjoyed participating since I discovered it a few weeks ago.
Concerning your eTrex - I have never owned one of these so I am no expert on them. But, if it is designed to accept data from the MapSource application (waypoints, routes, etc.) then I think all you have to do is specify what "port" on your computer the GPSR is connected to.
Up until last summer, this was easy - every GPSR out there used the serial port. Now, it is possible to connect by serial, connect by USB, connect by using a PCMCIA data card programmer - lots of choices.
On the "FILE" menu of MapSource, go to the "Save To" command, and select the appropriate connection method for your GPSR. It's probably serial for the eTrex series, perhaps there is an eTrex owner out there who can confirm this. You will then get a modal dialog box that gives you the option of pressing an appropriate button for USB or serial, be sure the serial button is pressed, and the appropriate com port is selected. I think there is an "Autodetect" feature in that dialog box you can use as well.
Lastly, check to see if you have the latest version of the MapSource application. The current version is 5.4, and if you have any previous version installed (all the way back to 2.0, the original release) you can download a free update from the Garmin website.
PanEuropean