Hi Sebastian,
Yesterday after uninstall and reinstall both LV7.0 German and PCI-CAN\2 v2.2, the system works again properly, I did not undertand why. (But this time after LV installation, I restarted the PC and then ran the LV by going through some example VIs, then restarted again and installed CANcard driver, I guess maybe activating LV once before installing Hardware drivers is very important.)
regards.