Hi.i have a reebok treadmill and the oil light has just lit up.i dont have instructions any idea were oil goes as doesnt seem to be a reservior anywhere?

You probably have to lubricate the surface of the shafts that spin the running surface.  I think that if you look around at treadmill maintenance posts, you will find some people referencing spraying silicone onto these.  That is the only appl;ication of any oil/lube that I could think of anyway in this case.