I was having the same problem, my Anti Virus, Norton Security Suite, just recently made the trainer manager untrusted and blocked it, had to unblock it in the firewall settings.
Now it works fine again!
[Edited by wingers17, 4/29/2013 12:22:05 PM]
I probably have this problem right here. I mean all my trainers work fine mind you...and the TM does what it's supposed to do on a basic level...sees all the trainers, lets me run them, etc.
So since it's a resent thing...Likely some update decided to hate on meh TM! Gonna' check that and see if I can fix it!