how can iget parts and fix my treadmill New fitness AS01?

Can anyone help? I have a "New Fitness AS01 treadmill and can not get any info from Treadmills Direct who supplied the treadmill on where to get replacement parts and advice on what may be wrong with it. The treadmill seems to be ok until pressure or weight goes on it and then blows a fuse (honest i'm not that heavy either!!) When the fuse or trip switch is re-set and i run on it and more or less force it round it will keep going for a wee while longer b4 tripping the fuse again. Does anyone know what i can do or can i get parts from any other suppliers for this equipment? thanks