PILOT STUDY: Patients receive oral erlotinib once daily. After 1 week of erlotinib alone, patients also receive oral temozolomide once daily for 6 weeks and undergo concurrent radiotherapy 5 days a week for 6 weeks. After completion of radiotherapy, patients continue to receive erlotinib once daily alone in the absence of disease progression or unacceptable toxicity. Beginning 4 weeks after the completion of radiotherapy, patients also receive oral temozolomide once daily for 5 days. Temozolomide treatment repeats every 28 days for 6 courses in the absence of disease progression or unacceptable toxicity.