Erlotinib may stop the growth of tumor cells by blocking the enzymes necessary for their growth. Radiation therapy uses high-energy x-rays to damage tumor cells. Drugs used in chemotherapy work in different ways to stop tumor cells from dividing so they stop growing or die. Combining erlotinib and radiation therapy with combination chemotherapy may kill more tumor cells. Phase I trial to study the effectiveness of combining erlotinib and radiation therapy with combination chemotherapy in treating patients who have inoperable stage III non-small cell lung cancer