To assess the safety and tolerance of multiple oral doses of 141W94 alone, in combination with 1592U89, and in combination with Retrovir and Epivir, administered to patients with HIV infection as measured by the development of clinical adverse experiences and laboratory test abnormalities. To determine the steady-state pharmacokinetics of 141W94 alone and in combination with 1592U89 after multiple oral dosing. To obtain preliminary evidence of antiretroviral activity of 141W94 alone and in combination with 1592U89, the antiretroviral effect of combined Retrovir/Epivir and the antiretroviral effect of 141W94 when added to Retrovir/Epivir or to 1592U89/Retrovir/Epivir.