Ache onde esta o registrador onde se encontra o bit chamado PBADEN, no datasheet do 18F44J10 ou 18F25J10, e ganhe um premio.
Referencias sobre o bit PBADEN encontradas nesses datasheets:
1-By programming the configuration bit, PBADEN, RB4:RB0 will alternatively be configured as digital inputs on POR.
2- Configuration on POR is determined by the PBADEN configuration bit. Pins are configured as analog inputs by default when PBADEN is set and digital inputs when PBADEN is cleared.
3- The POR value of the PCFG bits depends on the value of the PBADEN configuration bit. When PBADEN = 1, PCFG<3:0> = 000; when PBADEN = 0, PCFG<3:0> = 0111.
4- The PBADEN bit in Configuration Register 3H configures PORTB pins to reset as analog or digital pins by controlling how the PCFG0 bits in ADCON1 are reset.
.