OBJECTIVES: I. Determine the maximum tolerated dose of L-778,123 in patients with recurrent or refractory solid tumors. II. Evaluate the safety and tolerability of L-778,123 including qualitative, quantitative, and dose limiting toxicity in these patients. III. Assess the pharmacokinetic profile of this regimen in these patients. IV. Evaluate the radiologic or tumor marker responses to treatment in these patients. V. Evaluate the relationship between ras mutations and response to treatment in these patients. VI. Determine the relationship between plasma drug levels and farnesylation assay results.