This study will examine the use of a radioactive monoclonal antibody called yttrium 90-labeled humanized anti-Tac (90 Y-HAT) for treating certain cancers. Monoclonal antibodies are genetically engineered proteins made in large quantities and directed against a specific target in the body. The anti-Tac antibody in this study is targeted to tumor cells and is tagged (labeled) with a radioactive substance called Yttrium-90 (Y-90). The study will determine the maximum tolerated dose of 90Y-HAT and examine its safety and effectiveness.