Nevermind guys, reading around the posts it seems that the dev builds have been pulled. I guess they want us to only use the recommended builds.. which i'm fine with apart from the fact there are still huge bugs. I mean, my server i run is purely basic voltz, no mods, no addons what-so-ever, and the fact that a massive flaw (sod all uranium to mine) is pretty much a big problem in a mod pack where uranium is heavily required for alot of cool stuff. Ok i guess as admin hell i can spawn in and give myself infinite uranium i need, yeah that's what i'm gonna have to do as i have no choice in the matter.. I've rolled back to 1.0.11 on the server, copied the world folder and all seems to have transferred ok. I'm running the client launcher as Rec build now and able to join again.