it sounds like you and I are on the same boat. I sent an email out to RNGPS and I am waiting on some troubleshooting steps. This started last saturday for me, running 2.3.9 as well on an HTC PRO, (TRIED IT ON pro 2) .The uploads just keps failing after the progress bar is almost complete,or sometimes complete.
It seems to me like the prob happens at the server level.If i find anything I will let you know.
I uninstalled, soft reset, reinstalled,reset, deleted training data from my phone, ......NOTHING worked so far, but I AM hopeful it will get sorted out.For now, you can keep your training data on the HTC or upload it manually, i mean just enter it manualy.
After the latest update (2.3.9b) I can't no longer upload my trainings :-(
I have restarted my phone (HTC Legend), downloaded the program once more and installed it, but it still won't work.