Hi - could it be the oven temperature is too high? I have never made this bread mix, so I am not sure. Did you use the oven temp recommended on the package? Could your oven thermostat be wrong? I bought an oven thermometer to use in my oven to check the temp.
Or, try a shallower pan. That way I think it would bake through better without burning.
I am not much of a baker myself, but these suggestions might help. Good luck!