Yes, if you're using it for Dolphin you should use the Zadig steps described at that link instead of using vJoy.
If you're using the adapter for things other than Dolphin, I'm not sure if there's a great alternative to vJoy. But either way, uninstalling vJoy is what you should do if you want to get Dolphin to open.
If you're using the adapter for things other than Dolphin, I'm not sure if there's a great alternative to vJoy. But either way, uninstalling vJoy is what you should do if you want to get Dolphin to open.