Chrono Trigger Arris Dome

I'm supposed to push L+R and A to get to the door thing but it doesn't work when I try. I already tried assigning L R and A to one key, or 2 to 1 key and the other to a different one. Is there any other way to do this?
If it helps I'm using the No$gba emulator

Set L and R to the ctrl and shift key.You can hold those two down and hit whatever button you assigned the A button to and it should work.Worked for me anyways.

Worked perfectly, thanks!

Thats my problem to... this work for me... try it!If this not work try another keys!

If you want to use the standard controls you can just press the L+R then click on the touch screen. Touch screen is all about the AAAAAssss...