Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Erlotinib may stop the growth of tumor cells by blocking the enzymes necessary for tumor cell growth. Radiation therapy uses high-energy x-rays to damage tumor cells. Combining erlotinib with docetaxel may make the tumor cells more sensitive to radiation therapy and may kill more tumor cells. Phase I trial to study the maximum tolerated dose (MTD) of combining erlotinib with docetaxel and radiation therapy in treating patients who have locally advanced head and neck cancer