Well, my response was really to Arckenver. I'm just now reading and understanding the issue, thanks.
The earliest version of the plugin is 0.1 (it's still pre-release), and the issue existed from then (which means the plugin was initially built with 4.x API, and there are no early versions with 3.x API). It would be nice if plugin developers, just like mod developers, made plugins that could work with multiple versions of Forge.
I don't know what to do now. I really need a land management plugin for my 1.8 server. I really liked the concept of this one, more than Towny. I would prefer if I had a land management plugin which didn't rely on an Economy plugin to work.
I'm hoping that @Arckenver or someone else can make a land management plugin where the admins assign plots of land. It should be easier than making a plugin that allows players to buy/sell land. I really don't care for the buying/selling land features. I see why some server owners would want buying/selling land to be possible, so I'm not saying there shouldn't be plugins for that, but I wish there were more simple plugins for land management without buying/selling.