Why wont my pilot light for fridge stay lit?

When i try to run my fridge from gas i can light the pilot light but evenif i hold in the nob for over 20 seconds the pilot light does not appear to stay lit. the fridge works fine on 240v so the fridge itself is not the problem. would love to get the gas working , if anyone knows what the problem may be? also does not appear to work from the 12v battery?? all other electrics are fine. i have an eriba puck caravan.