AssetBundle.mainAsset works but not .Load("name")

Code: http://pastebin.com/R6PmTtP7

Situation: I have a prefab called "PeekABoo" (checked spelling), which contains a few scripts and some childs.

I use the Bundle Export Script from the Unity3d website to export it.

To export it, i right click the "PeekABoo" prefab and export it with Tracking Dependency.

But if i want to spawn it, it works when i use "mainAssets" but not when i use "Load".

Anyone an idea what could be wrong?

Thanks!