Hmm... That’s really strange, What I did:

1. I deleted the line with \writebetweenlist and compiled the file. It worked.
2. I put back the line and triode to compile -> fatal error
3. I commented out all the lines which had something to do with the table of contend -> fatal error
4. I changed all back -> fatal error (as expected)
5. I commented out all the lines in my project files (all the lines with \input and compiled and got an empty file witour errors.
6. I deleted the comment signs one after the other and compiled every time -> no error
7. All was how it was, so I entered the \writebetweenlist (absolutely the same: copy and paste) and ... Tatarata! It works...

An enigma. I effectively changed nothing, all is now as it was before. Very, very strange…