THE ARDUINO HIGH STRIKER (HAU DEN LUKAS)

Does this refer to 1 pin, or two:

pinMode ( remotePins [Info][0], OUTPUT);

My guess is that remotePins [ x ] [ y ] would store 2 values, yes?

I didn't think pinMode would assign 2 pins as outputs at one time.

maybe you could try this instead to set up the pins as outputs:

for ( byte Pins = 2; Pins<10; Pins = Pins +1 )
{
pinMode ( Pins, OUTPUT );
}

Also, maybe just a typo in your question,
"I want to connect my Arduino "on one side" (INPUT PIN 12) with a light barrier;"
but pin10 seems to be used vs pin12:

int lightbarrierIN = 10;