Patients receive oral temozolomide once daily on days 1-42 and undergo concurrent radiotherapy once daily on days 1-5, 8-12, 15-19, 22-26, 29-33, and 36-40. Four weeks after completion of radiotherapy and temozolomide, patients receive oral temozolomide once daily on days 1-5. Treatment with temozolomide repeats every 28 days for up to 12 courses in the absence of disease progression or unacceptable toxicity. Patients also receive oral erlotinib hydrochloride once daily beginning on day 1 of radiotherapy and continuing in the absence of disease progression or unacceptable toxicity.