Patient are being asked to participate in this study because they have been diagnosed w/advanced solid tumors for which no effective therapy exists. This study is being done to test a new drug called J-107088 targets an enzyme called topoisomerase I that is important to the growth of tumors. The goals of this study are (1) to identify the side effects of J-107088 over a range of doses; (2) to determine the safest dose of J-107088; (3) to measure how quickly and effectively J-107088 is cleared from the body; and (4) to describe any antitumor effects of J-107088. SPECIFIC ENDPOINTS: 1) Determine the maximum tolerated and recommended Phase II dose(s)s of J-107088 when given as a one hour infusion twice weekly for two weeks every 28 or 35 days 2) Investigate the clinical pharmacokinetic and pharmacodynamics of J-107088. 3) Describe the toxicities of J-107088 both qualitatively and quantitatively.