Hi Ararat,
When you work with automation’s then it’s my experience that one of the things that often goes wrong is the versions. In your case that “could” be the problem. Normally when you install NAV or the prerequisites, then you should be able to compile all objects without additional installs. Are you able to compile codeunit 99008516?
If yes, how did you create the automation variables in your new code? If you created them manually, then this may where you could have choose the wrong version of the automation. If you copied them, then they would most likely be ok.