From the datasheeet:
"By (power-on) default these pins are configured as analog inputs, i.e., “1” written in the corresponding Port 1 register bit. To configure any of these pins as digital inputs, the user should write a “0” to these port bits to configure the corresponding pin as a
high impedance digital input."

So the code is correct. That leaves the hardware, either something is not connected properly or the ADuC812 itself is bad.

Jacob