Snes Mini Control problem

I use retroarch 1.0c for the snes mini and it works great for GBA. However I also use it to run N64 game Mario kart 64 and i can get the controls to work, but randomly when gaming the Z-trigger button stops working. And when the map changes in the game the button works again, until it happens again…

Another problem is that inside the Retroarch menu (Select - Start) i cant go back, so when i want to change something else than the menu im inside i need to restart the game.

Anyone have any input on these problems?