This phase I trial is studying the side effects and best dose of GTI-2040 and gemcitabine in treating patients with metastatic or unresectable solid tumors. Drugs used in chemotherapy, such as gemcitabine, work in different ways to stop tumor cells from dividing so they stop growing or die. GTI-2040 may stop the growth of tumor cells by blocking the enzymes necessary for their growth and by making tumor cells more sensitive to gemcitabine