OBJECTIVES: Phase I: I. Determine the maximum tolerated dose (MTD) of oral topotecan combined with a fixed dose of paclitaxel in patients with advanced non-small lung cancer (NSCLC) and other advanced solid tumors. II. Determine the response rate of NSCLC patients treated at the MTD of oral topotecan combined with intravenous paclitaxel. III. Determine the dose limiting toxicities of this drug combination in this patient population. Phase II: IV. Determine the toxicities of this regimen at its MTD in patients with NSCLC. V. Determine time to response, response duration, survival, time to progression, and rate of stable disease of patients with NSCLC treated with this regimen at the MTD. VI. Assess changes in well-being of patients with NSCLC treated with this regimen at the MTD.