DISEASE CHARACTERISTICS:

• Histologically confirmed solid tumor that is refractory to standard therapy or for which no standard therapy exists
• Measurable or evaluable disease
• No known untreated or symptomatic CNS metastases
• No concurrent hematologic malignancies

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 9 g/dL (erythrocyte transfusions allowed)

Hepatic

• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• ALT and AST no greater than 2.5 times ULN (5 times ULN if liver metastases present)

Renal

• Creatinine clearance at least 50 mL/min
• Potassium at least 3.4 mEq/L
• Calcium at least 8.4 mg/dL
• Magnesium at least 1.2 mEq/L

Cardiovascular

• QTc interval no greater than 450 msec in males
• QTc interval no greater than 470 msec in females
• No other electrocardiogram abnormalities

Other

• Able to swallow capsules
• No gastrointestinal disorder that would interfere with oral drug absorption
• No serious concurrent systemic disorder
• No compliance issues that would preclude study
• No geographical conditions that would preclude study
• No active infection
• No prior hypersensitivity to any component of study drugs
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 3-6 months after study

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No concurrent immunotherapy
• No concurrent routine filgrastim (G-CSF)

Chemotherapy

• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin)
• No other concurrent chemotherapy

Endocrine therapy

• At least 4 weeks since prior anticancer hormonal therapy
• At least 6 weeks since prior bicalutamide
• At least 4 weeks since prior flutamide or nilutamide
• Concurrent luteinizing hormone-releasing hormone analog therapy (e.g., leuprolide or goserelin) allowed for patients with prostate cancer if started before study entry
• No other concurrent hormonal therapy

Radiotherapy

• At least 4 weeks since prior radiotherapy
• At least 2 weeks since prior palliative radiotherapy
• No concurrent radiotherapy (including palliative therapy)

Surgery

• Not specified

Other

• Recovered from prior therapy
• At least 4 weeks since prior investigational anticancer therapy
• At least 4 weeks since other prior anticancer therapy
• At least 30 days since prior experimental drugs
• No other concurrent experimental medications
• No other concurrent anticancer therapy