A friend of mine told me that people who backed PA (I was a 100$ backer) would get a key for PA: Titans. Also, PA stopped working the day it was officially released because it would fail to load and hasn't worked for me since.
Yeah, backers got it for free, so you should have it. If you used Steam, it would have appeared in your library automatically and if you use the UberLauncher, the game would simply be updated with the Titans content. Number one reason for PA not working is outdated drivers. So if you are on Windows, post your DxDiag.txt. You can make one by pressing <WinKey>+R, type "dxdiag" and upload the resulting file here using the "Upload a File" button on this forum.
I'd bet more on an outdated mod, since it did work until a big patch (release) hit. Were any mods installed? Make sure they're all disabled for tests.
Is there a way to put PA: Titans on Steam? I think it would be registered to the UberNet account because I'ma kickstarter backer. Thank you so much for the quick response.