If you are assigned to take cetuximab and erlotinib, cetuximab will be given by vein once every week. The first time you receive cetuximab, it will be given over 2 hours. All other infusions will be given over 60 minutes. Erlotinib is taken by mouth every day during the 28-day study cycle. You should take erlotinib on an empty stomach either 1 hour before eating or 2 hours after eating.