Well, i can't compile the mod without it, and as i don't see any download links, where to get the mod from?

Setup a new forge workspace and drop in the code.

Seems like theres something wrong...(I'm getting that too)

I can compile just fine. I am using the recommended forge.
Also make sure you have the line mappings = 'stable_12' in the minecraft section of build.gradle
(Don't forget to recompile forge after adding this line.)