Some possibilities are:
1) The jumpers on the MAX1464 evaluation board are not properly set.
2) The MAX1464KEY, the jumper setting, and the configuration settings are not consistent for 3-wire or 4-wire communication.
3) The computer serial port has a problem.
4) The MAX1464 evaluation board is damaged.
5) The MAX1464 chip on the evaluation board is damaged.
6) The MAX1464KEY is damaged.