I know your problem, i've got it myself a few days ago with the steam version and the trainer 18.104.22.168. Whenever i tried to access the inventory, the game just crashed.
But there is no need for an update, trust me! It may sound crazy but in my rage, i deinstalled the game and the trainer. I reinstalled the game (not necessary for the "cure" and accidentally downloaded the trainer 22.214.171.124 instead of the newer one. I didn't notice it first but when i started the game - it worked! So, what you have to do is simply download the 126.96.36.199 trainer, it will work on the Steam Version! I promise!