RATIONALE: Drugs used in chemotherapy, such as cisplatin and capecitabine, work in different ways to kill tumor cells or stop them from growing. Radiation therapy uses high-energy x-rays to kill tumor cells. Monoclonal antibodies, such as cetuximab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Cetuximab may also stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. It is not yet known whether giving cisplatin together with capecitabine and radiation therapy is more effective with or without cetuximab in treating esophageal cancer.