It sounds like the switches for your left and right ramp may be flip-flopped. I had a similar issue on mine and simply swapped the switch plugs underneath the playfield.
Quoted from Rdoyle1978:Quick question for the other owners -
In our Creature, when I activate Unlimited Millions, then go up the left ramp... is the game supposed to do something? I get no points, nothing changes, and eventually the mode times out. The ramp switches appear to function in test mode and I get 100,000 points for hitting the left ramp during normal play... any ideas? I know it's Unlimited Millions since it appears on the DMD
Also, I've noticed the wrong lamps are lighting on the mode cards - e.g. Mega Millions lights when it's Creature Feature, and none of them seem to be correct. This points to a wiring mismatch somewhere (no clue to to start on THAT one), but not sure if it's related to the above.