BMP to PP256 Format?

[KoVeNaNT]

I get an Illegal function call here:

Code:

sy = 12
sx = 11
Offset = 0
FOR X = sx TO 300 STEP stx
FOR Y = sy TO 170 STEP sty
            GET (X, Y)-STEP(stx - 1, sty - 1), BMPS((Offset * Size))    ---- HERE
            LINE (X, Y)-STEP(stx - 1, sty - 1), 255, B
            Offset = Offset + 1
NEXT Y
NEXT X

It's silly maybe, but I haven't been coding for years so I need a little kick-start to get me going again...

Here's the dimensions of my sprites/tiles: 20x16
The BMP's dimensions is: 320x128

I also changed this:

Code:

FOR Y = 0 TO 199
FOR X = 0 TO 319
    IF POINT(X, Y) = 106 THEN
        PSET (X, Y), 175
    END IF
NEXT X
NEXT Y

To this:

Code:

FOR Y = 0 TO 127
FOR X = 0 TO 319
    IF POINT(X, Y) = 106 THEN
        PSET (X, Y), 175
    END IF
NEXT X
NEXT Y