If you are using the 3.4 beta build for 1.5.1 the plugin will say that there is a new version available - This is because you are currently not using the recommended version of WorldWarp.
WorldWarp is a basic, Yet effective way of managing your worlds. The plugin lets you Create, Import, Delete, List & Warp to different worlds just by typing some easy commands. WorldWarp features a powerful world creating system which lets you choose between Normal, Nether & The End - And lets you specify the seed you want to use.