Update: Even installing new apps seems to fail :/ After (successful) install of googleServicesFramework.apk and vending2.2.11-signed.apk I tried to install some browser from the market. This failed after download. I didn't care because it's known that lot of apps don't work. After that I transferred Moon+ Reader and Aldiko via Dropbox. At least Moon+ should work I think. But when I try to install them directly (I use Root Explorer to navigate to the APKs), Root Explorer crashs after I choose "Install" in the Message Box that asks me what to do with the APK.
Could be the case that I installed Update to 1.0.05 _after_ rooting the device? I have a Roadkil image of 1.0.03, should I recover this?