Thanks guys for replies
Dave, in my case all files are in their correct places, I have no loose files in wav directory, except for pfclick and radio noise files, there's nothing I could move anywhere, there are also no sub directories in proflight dirs.
Philouz, I don't have extension pack yet, and honestly I don't feel like buying it before my base pack works correctly, but thank your for your input, this shows that there must be some internal bug
Tomorrow I'll try some short flight with higher debug level, maybe log file will show something.
Regards,