problems with multiple encoders, please help!

[robself705]

we're using a total of 4 encoders on our robot, 2 for steering, and 1 for a turret. but when any more than 1 encoder is defined, only the one that is defined first works. here is a sample of some code that only read one of the encoders in teleoperated mode

Encoder front(1,2);
Encoder back(3,4);

while (1)
{
printf("%d %d\n", front.Get(), back.Get());
}

front.Get gives back a value when we turn the encoder but back.get does not, we've checked the wiring a hundred times, any help would be greatly appreciated