Unable to modify backup

I'm trying to modify the time of a schedule backup in Windows Server Backup on a server running 2012 Essentials.

Normally I'm able to do this without any problem but when I try to do it here I get the error "The System cannot find the path specified." This is what happens whether using the GUI or wbadmin.

Any ideas as to how to fix this short of deleting the backup job and recreating it?

Jonathan