Inside your alias file you have being using this on an alias name ' ' share the code or a picture here. It says u have being using them in the error that ur showing in ur post so should be easy to fix. Just with a little time of reading
I searched in the file and there's no ' ' in it.I just did everything it says here nothing more:https://confluence.ugx-mods.com/display/UGXMODS/Custom+Main+Menu+Music
On your modbuilder at fastfile mod.csv do you have any '' of those ?
If not im not really sure, something ive never being having issues with.
U can try copy one other file and paste it and then rename it to that soundalias file name and then copy paste the code inside it and see if that works. But it dosent make any sense
Actually I removed it because the sound doesn't shows up as garbarloop.wav in my computer,but just garbarloop.I tried both ways and I keep getting the same error