Just dont upgrade Training Center to the latest version if you plan to upload courses.
Is the 3.00 working for you? I downloaded it, and the GPS does nothing. No satellites appear at all. I tried downloading the GPS receiver add-on that pops up after the software download, but it just hangs and nukes the USB drivers. I just reinstalled 2.90. Emailed Garmin tech support, and they were not helpful at all. I don't think they read emails. Just look at the topic and send you a canned FAQ response.
I put on the 3.0 with webupdater. That loaded fine, but then the GPS didn't do anything when I turned the unit on. Just the secondary update (which I shouldn't have needed anyway) crapped out upon download. I tried to run a fix and reinstall too. Same thing. No satellites blinking or anything on the acquiring satellites page. I put 2.9 back on manually.