PART B (alvocidib and FOLFOX): Patients receive alvocidib IV over 1 hour, oxaliplatin IV over 2 hours, and leucovorin calcium IV over 2 hours followed by fluorouracil IV continuously over 48 hours on days 1, 15, and 29. Courses repeat every 42 days in the absence of disease progression or unacceptable toxicity. Tumor tissue samples may be collected periodically for further laboratory analysis.