To compare the safety, toxicity, and tolerance of two doses of ribavirin in combination with didanosine (ddI) to HIV-infected children. To determine the toxicity of ddI/ribavirin and compare it to the expected toxicity of ddI monotherapy. To determine the effect of concurrent ribavirin on the pharmacokinetics of ddI. To determine a dosage of ribavirin that would be suitable for a Phase II/III evaluation of ddI/ribavirin.