Patients receive 17-N-allylamino-17-demethoxygeldanamycin (17-AAG) IV over 2-6 hours on days 1, 4, 8, and 11. Treatment repeats every 21 days for at least 6 courses in the absence of disease progression or unacceptable toxicity. Patients achieving a complete response (CR) receive at least 2 additional courses beyond CR. Patients achieving a partial response receive at least 4 additional courses beyond their maximum response. Selected patients may receive additional courses of therapy beyond the protocol guidelines at the discretion of the principal investigator.