Inclusion Criteria:

- STRATUM I INCLUSION:

- Each patient must have a proven pathologic diagnosis of solid tumor; the tumor must
be refractory to conventional therapies, or for which no effective therapy is known;
patients with brain tumors are eligible, but they should not be receiving
anticonvulsants; the requirement for histologic diagnosis can be waived for patients
with brainstem gliomas

- Karnofsky >= 50% for patients > 10 years of age; Lansky play scale >= 50% for
children =< 10 years of age; neurologic deficits in patients with CNS tumors must
have been relatively stable for a minimum of 2 weeks prior to study entry; patients
who are unable to walk because of paralysis, but who are up in a wheelchair will be
considered ambulatory for the purpose of assessing the performance score

- Life expectancy >= 8 weeks

- Nutrition status >= 3rd percentile weight for height and serum albumin >= 2.5 g%

- Prior therapy: patients must have recovered from the acute toxic effects of all prior
chemotherapy, immunotherapy, or radiotherapy prior to entering this study, and must
be without significant systemic illness (e.g., infection, fever, mucositis, severe
anorexia, and severe malnutrition)

- Myelosuppressive chemotherapy must not have been received within 3 weeks of
entry on this study (six weeks if a prior nitrosourea)

- Biologic, anti-neoplastic agents must not have received at least 1 week

- Radiation >= 2 weeks must have been elapsed from prior local radiation (small
port); >= 6 months must have been elapsed from prior craniospinal radiation or
>= 50% radiation of the pelvis; 6 weeks must have been elapsed from substantial
bone marrow radiation

- Autologous or allogeneic BMT without TBI >= 6 months must have been elapsed,
with no evidence of GVH disease

- Growth factor(s) must not have been received within one week of entry on this study

- Steroids: patients with CNS tumors who are receiving dexamethasone must be on a
stable or decreasing dose for at least 2 weeks prior to study entry

- ANC >= 1,000/ul

- Hemoglobin >= 8.0 g/dL

- Platelet count >= 100,000/ul

- Bilirubin =< 1.5 mg/dL

- SGPT =< 2 times upper limit of normal

- Albumin >= 2.5 g/dL

- Normal serum creatinine for age or, if abnormal serum creatinine, normal GFR for age

- All patients (or their legal guardians if patient is less than 18 years of age) must
sign a document of informed consent that has been approved by the Institutional Human
Review Committee; when appropriate the patient will be included in all discussions in
order to obtain verbal assent

- The Phase I Office must give permission to register the patient; registration must
occur on the day the patient receives the treatment; however, the registration should
precede the drug administration

- Protocol must be approved by the local Institutional Review Board (IRB) prior to any
patient registration and reapproved every twelve months

Exclusion Criteria:

- STRATUM I EXCLUSION:

- Pregnant or breast-feeding women will not be entered on this study; pregnancy tests
must be obtained in girls who are post-menarchal; males or females of reproductive
potential may not participate unless they have agreed to use an effective
contraceptive method

- Patients who have uncontrolled infections are not eligible for this study

- Patients who are receiving any other chemotherapy or investigational agents are not
eligible for this study

- Patients who are receiving anticonvulsants are not eligible for this study

- STRATUM II EXCLUSION:

- Patients who have received more than two prior chemotherapy regimens (single or
multi-agent regimens)

- Patients who have had central axis radiation

- Patients with bone marrow involvement

- Patients who have had prior stem cell transplantation (with or without TBI)