Beginner needs help to read an analog input

I am trying to measure an analog input with rabbit 4500 using the following sample code:

#use XBEE_API.LIB

#define DIO_00 XBEE_IO_CONF_ANAIN

main()
{
int error;
error=0;
if (zb_io_init() == 0){
printf("Inicializacion %d
“, error);
while(1){
printf(”%d
", zb_adc_in(0));
}
}
}// end of main

zb_io_init() always returns values not equal to zero and the codes ends. Could someone help me to obtain the analog value???

Thanks.

Any one out there? Is the XBEE_API.LIB still supported? Where would one find documentation?

Thanks