Unfortunately I can't open your project, but I'm guessing you mean something like this:
x = int(object.X/32)*32
The above will set object to the closest multiple of 32.
The idea here is that the value, object.X will be divided by the grid size you want, and then rounded up/down or in this case to the closest whole number, then multiplied by the grid size again to get it back to it's proper size. In effect, it rounds to the grid size, since when int() is applied to it at a 32nd the size, it's rounding to 32x the normal size. Or something.