Well I already did reply about that.
You asked again for it, which is why I replied to it again.
Anyway where can I find this paintkit ?
It's were it has always been, here in this forum section. However, if you never installed it, you don't have to updated it. You can check if you have installed it (and maybe forgot about it) if there are some GSX objects with names containing the _USER string, under the FSX\Simobjects\Misc folder. If you don't have them, it means you installed the Paintkit in the past, so you will have to update it.
If you haven't, then I'm sorry, but the only possible explanation for your problem, is that you are not installing the current GSX version, but an older one.