This phase I trial studies the side effects and best dose of bortezomib when given together with fluorouracil and leucovorin calcium in treating patients with solid tumors that are metastatic or cannot be removed by surgery. Bortezomib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as fluorouracil and leucovorin calcium, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving bortezomib together with chemotherapy may be an effective treatment for solid tumors.