You have to fix syntax errors in your files. Program tells you exactly which file is broken. If you still are not able to find where error is, upload it here and I will help you.
Thank you for youre reply. So i think i fixed the error in my files, so i got it working. But somehow the vehicles driving now complete different and some feeling broken. It is maybe possible that the merger messed some stuff up? (btw. here is a link to one meta file that had a error, it still giving it, maybe you can show me what type of error is in there: handling.meta)
Program does not touch values in any meta file. It just copies them to one file. I think it feels different now cuz that part of file started to load in properly after you fixed it. You can verify if values are the same between not merged and merged file using visual studio code or notepad++.