Hi Jared,
Planes.dlo is a file from Forest Pack Pro 2, an old version of the plugin.
You can find a recompiled version of Forest 2 in the latest beta package (Forest Pro 3.3.5b). It is not installed by default, you must select it in the setup program (Legacy Plugins).
Once installed the Forest 2 files, you can overwrite the Forest 3 installation with the version that you need, as 3.3.1.