I've used TWRTrainer many times without any issues, however, today it (all of a sudden) stopped working. In preparation for a training session, I tried loading in a .apt file, after which TWRTrainer gave me the following error and immediately quit:
I tried running the .exe in compatibility mode for Windows XP and in Administrator mode, neither of which solved the problem. I also replaced my TWRTrainer (and .apt) files with those of my training administrator, but this didn't solve the problem either. It happens with every .apt file, even the included file for Burlington.