Problems with the Apple Adapter and Samsung P2250

[hornedry2k]

Today i bought a new Alienware PC and three Samsung P2250 Monitors. First i tried a normal MiniDP -> DVI Adaptor but that dont work. Then i try the active Adapter from Apple and it works but when i want make one Monitor (Create Group) all Monitors goes black and desktop, black and desktop like Disco.

Is that Adapter not good for Eyefinity ???

Or what can this be ???

I use the newest ATI Driver and Catalyst Software but it dont work :?