With a fresh install of battlecode using intellij, even after running the update, I'm getting a lot of errors. Pic attached. I don't think I'm doing anything wrong, but if anyone has any ideas please share.
I had issues because I needed to install the Ant plugin to run "Update Battlecode" but that doesn't look like your issue...
This looks like IntelliJ is having trouble seeing the battlecode source code. Try running Ant Update, and making sure that IntelliJ has ant enabled.
deleting bin/ and lib/ helps sometimes!~