Error Tracking

I'm receive the following error and would like to know where it is coming from:

Warning[202] c:\basic working\handhe~1.mac 210 : Argument out of range. Least significant bits used.

He is the section from the macro I think it is talking about. These are lines 204-215 which the bold section being 210. Anyone know how to track the source of this type of an error.

Code:

---

SUB?WCB macro Win, Cin, Bout
    if (Cin == 1)
        CHK?RP  Win
        decf    Win, W
        MOVE?AB Bout
    else
        movlw  Cin
        CHK?RP  Win
        subwf  Win, W
        MOVE?AB Bout
    endif
    endm

---