Hmm... sounds to me like LW may have crashed - ten minutes is waaaay too long for the booleans to take, hell, even on an old 386 they shouldn't take that long (assuming you could get lightwave to run on an old 386 that is
)...
Cancel the boolean operation (if you can), otherwise, quit lightwave and get it back into a workable state, but before you try doing the boolean again, try moving your cutter object a little - it can sometimes have problems if there are polys that are trying to be cut along an edge for instance...