bug reports are good, they greatly help me to remove bugs from the bug, so don't hesitate to go on with the reporting !
(although, I'd have preferred if you had an Intel Mac, so I could have looked into your saved games...
So, I fixed the problem of the travel button ; now, it's not possible to click on it when the player doesn't have enough money.
To fire a trainer from the Team screen, you just need to click on the "Pay" button for all players paying this trainer.
Once your player doesn't have cash anymore, Team members won't travel with him.
Unfortunately, I couldn't reproduce the bug leading to "no one was available to pay his salary" message & hanging...
To avoid force-quit, if you are in windowed mode, use the system menu to quit the game.
If you're in fullscreen mode, maybe use apple+q or something like that (on Windows, it would be Alt+F4).