If you're talking about the TCX to Nike+ uploader here, http://www.awsmithson.com/tcx2nikeplus/, I don't think the TCX upload option works any more (Nike changed something on their site to break it?). At least, it never has for me.
It worked fine for me this last monday, September 17th when I successfully transfered a track with GPS data. The ony secret was to make it public = unlock.
But for indoor track (without GPS) data I did not succeed.
These days i connected and synced lots of apps (Fitbit, Nike+, Endomondo, Garmin Connect) - it's like a Zoo, but really nice to play with =)