Yeh, I think that the focussing problems were at the long end. I don't really see the point of VR on a zoom lens when you can't focus at the long end in low light. If you can't even focus or make the shutter go, then VR is pretty much useless.
Camera settings can be changed to aid in this situation. For example, to allow the camera's shutter to fire even when the lens isn't on green-light focus. Some cameras default settings don't allow this.
I have to say I'm not a fan of VR, I've never seen good results from it and really just see it as an uneccessary battery drain.
lens was new, so probably didn't need a service.
All of these are opinions are from this lens only though, VR might be good on other lenses, but not the one I had.
I do think that it's ludicrous that this lens is so popular though, when you can get the 80-200 for more or less the same price, and that is a tip top of the range pro lens with incredible optics and no gimmicks.