that might be something to try if all else fails, but really id make a new mesh folder, then set honorbuddy to use that, so it redownloads the meshes it needs, and hopefully fixed that "Is null" error.
Well it's as safe as the normal version of HB, just that you get to try some of the new features the HB devs are working on.
You might get an error here or there as it's just a beta build but I used it before full release of HB for MoP and it worked pretty well.
Anyways the reason you should give it a try is to see if it's an issue with your current HB installation or if it's something else because my HB works perfectly fine so just to see what could be the cause of this other then meshes/cache etc