This error can be caused by a number of reasons.
First, let's make sure your computer meets our minimum system requirements.
Second, this can be caused by something being wrong with one particular car or track file.
Please follow the instructions in this FAQ: Loading Error 22
Third, This can also mean that you are trying to run a non dirt car on a dirt track. This works sometimes but not others so please try a different car/track combination.
Lastly, please try and rename your current Documents\iRacing folder to iRacing.old.
Then, the next time you launch the sim, it will prompt you to reconfigure your graphics and recalibrate your controller.
If this resolves your issue, and you have any setups, replays, or paint schemes, you will need to move them over from the iRacing.old folder to the new iRacing folder.