If you are in Phase I, on Day -3 of Cycle 1 (3 days before your first dose of study drugs), you will take erlotinib hydrochloride by mouth. On Days 1-19 of Cycle 1, you will be take dasatinib and erlotinib hydrochloride by mouth once a day. On Days 20 and 21 of Cycle 1, you will only take dasatinib by mouth once a day. Every day of Cycles 2 and beyond, you will take dasatinib and erlotinib hydrochloride by mouth once a day.