When you posted this question before, you made a reference to Sears, so I'm assuming that you're in the USA. (Also, the word 'lube' isn't used in British english).
A bit of web searching suggests that your treadmill might be manufactured or distributed by Icon (because I've found references to Performant Lube being the only product which should be used with their treadmills).
If I'm right so far, you might want to take a look at a list of some of Icon's retailers:
http://www.iconfitness.com/about/retailers
(Hopefully, you'll know which of those outlets might be worth trying. Most of those companies don't trade here in the UK).
Alternatively, you could try phoning the Icon Health & Fitness Customer Service Department on 1-800-999-3756.
(I assume that they would know where you can get hold of Performant Lube. Even if your treadmill is actually made or distributed by a different company, they should still be able to tell you where you can obtain the product, since they recommend it for their own treadmills).
Chris