Post the code you're having problems with. That makes it a lot easier
for folks to help.

Here's a simple test with 3 LED's connected to PortB pins 0-2 to see how
it's working.

Portb.0 -------|>|---/\/\/\--- gnd
Portb.1 -------|>|---/\/\/\--- gnd
Portb.2 -------|>|---/\/\/\--- gnd
Code:
A VAR BYTE
B VAR BYTE
C VAR BYTE

A = 1
B = 0
C = 1

Main:
    IF A = 1 then HIGH 0 ' PortB.0 LED on  
    IF B = 1 then HIGH 1 ' PortB.1 LED on
    IF C = 1 Then High 2 ' PortB.2 LED on
    Goto Main
LED's on RB.0 & RB.2 turn on while the one on RB.1 stays off.