 This phase II trial is studying how well giving imatinib mesylate together with paclitaxel works in treating older patients with stage IIIB or stage IV non-small cell lung cancer. Imatinib mesylate may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as paclitaxel, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving imatinib mesylate together with paclitaxel may kill more tumor cells 