Well, I can open Mario Party 6 on every revision. I also got that error before, as I opened dolphin on my PC (and also on the PC of my Aunt^^).
Just try to open it again... I think you get this error every time you first open dolphin on a PC (I think this is true for you?). Try out, if this doesn't help... lets see.
Just try to open it again... I think you get this error every time you first open dolphin on a PC (I think this is true for you?). Try out, if this doesn't help... lets see.