 - Phase I all solid tumor patients: Patients receive oral capecitabine twice daily on days 1-7 and 15-21. Patients also receive irinotecan hydrochloride IV over 90 minutes on days 1 and 15 during course 1 and all subsequent odd-numbered courses and oxaliplatin IV over 2 hours on days 1 and 15 during course 2 and all subsequent even-numbered courses. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity Cohorts of 3-6 patients receive escalating doses of capecitabine during both odd- and even-numbered courses until the maximum tolerated dose MTD is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients with at least 1 patient 65 years of age experience dose-limiting toxicity. At least 6 patients are treated at the MTD. 