OK - this is really weird. As you saw in my above post, I had been using my tablet this morning (still in bed - heh). Everything was working fine in the tablet, both on the web interface and on the Android Transmission app. But then, when I went on my HTPC (Transmission Remote GUI) - I encountered the very same problem as before!!!
So I just deleted my connection, re-connected, and all is good! Weird...I wonder if this was the problem all along...?? Anyhow, just a placeholder for anybody Googling this in the future.
Cheers!