Please can you update your plugin so it supports the latest version of Bukkit for Minecraft 1.2.3

It already does. There is a new API added for WGENs (the current one CR uses was deprecated in 1.2.x), however 1.1.x does not support the new API.

When 1.2.x hits RB I will be releasing a new version that has a few new features and uses the new 1.2.x API, but at present you should have no issues using v0.0.4 on 1.2.3.