Sorry, that I wasnīt so specific. I was already sleeping, when I wrote the question yesterday.
First I installed the newest Oracle VM and the newest Sailfish SDK:
> The Emulator started but didnīt work. There was some kid of problem with the BIOS.
The removed both an installed it again with an older version of Oracle VM (because I read something like that anyhwere):
> Didnīt work again.
The I installed the newest versions of VM and SDK:
> The MerSDK neither can be started from the Qt-IDE nor from the Oracle VM. I always get the Error:
The virtual machine 'MerSDK' has terminated unexpectedly during startup with exit code 1 (0x1). More details may be available in 'C:\SailfishOS\mersdk\MerSDK\Logs\VBoxStartup.log'.