1. When I start up the game it shows up on the side.
2. I'm testing content in a version of Trainz 1.3 I found online before I do anything with UTC.
3. Not do that. The error... the content should work.
You're using a very old version of Trainz so it may no longer be compatible with modern PCs. If I were you I'd just use T:ANE, since you have punched it already. I get that you want to test DLC in this version, but why not just test it in a newer model?