The BAM_PIN (PORTC,0, L1B) statements define the PIN used and the dutycycle variable.

But instead of a byte variable for the dutycycle, L1B, L2B and L3B are defined as the PINs again.

Change them to ...
Code:
L1B VAR BYTE ;PORTC.0 
L2B VAR BYTE ;PORTC.2 
L3B VAR BYTE ;PORTC.4