Games : Cannot get forge to work with minecraft 1.7.2

Playing specific custom maps that need mc 1.7.2, and trying to use a mod with forge, but am failing.

I'm using forge version 10.12.2.1121, the recommended version for 1.7.2. Download and run the installer, which reports successful installation. I start MC and select the forge profile and try to run the game, and then nothing. The MC launcher just closes. No errors, no crash reports. It just instantly closes.

Using win7, latest Java version, a brand new Minecraft install with NO mods yet installed.