Dirtybeaver

Hello, i require some help. I am very new to understanding the operation of this, and when i start my quester with Bambo 1-35 questing (Horde) and Combat Rogue Vanilla fight class, for a 1.12 vanilla. I get the same compilator error, any ideas on how i can fix this. i have litter understanding on what to do. There are more errors on every step, just this is the first one.