discogs.com Website Error

you don't have to care about "length". that is only visible in the web sources dialog window and not written into you files.

If you don't want %mixartist%, you can use dano's
normal script (discogs_07) /t/1992/1
but that leaves also other information away.

or you use my script /t/9226/1
It's different in installation, but it has the advantage that you can every single field you want to write without having to deal with Mp3tag's web script language. See the starting post there for instructions.