Leaking Propane Torch -- Have You Seen this Problem?

Some time ago I purchased a Bernzomatic Mini torch. I thought a pencil-thin flame would be useful for soldering small bits. However, when I plug it into a standard propane or MAPP cylinder, it leaks through a hole in the on-off knob (see the orange arrow in the picture). As near as I can tell, it must be leaking around the brass nipple that plugs into the gas cylinder but I can't see how this is possible. None of my other torch heads leak using the same cylinder and the dimensions of this nipple seem to measure exactly the same as for the others. A phone call to Bernzomatic reveals this product isn't in their data base anymore so they couldn't offer any help. I hate to trash this device because it looks like it should be useful. And it's really quite beautiful, too. Has anyone seen this problem before and is there a fix for it?

Who did you buy it from, can they not assist you? I would have thought it should be covered by a warranty?