Thanks for all the Support guys!
Here the Solution
1. Plug your Interface in your Computer as you usually do
2. Uninstall your MIDI drivers and divices you want to use and which were plugged in before
3. Plug a USB-Hub in and wait till its drivers are installed
4. Plug all your MIDI divices in the Hub and wait till their drivers are installed
5. Start MixVibes and be a happy guy !
Usen in this Set Up:
2x Technics SL1210
1x Reloop RMX 30 BPM Blackfire edition
1x U46MK2
1x Pair of Novation Dicers
1x LPD8
1x MixvibesCross 3.4.3