Hmm, yes, I've tested your working counters for CORE and, despite their being a bit bigger than vanilla ones (Kb-wise) they do work indeed. That's odd, since every time I've made a 8-bit file bigger than its original size it wouldn't work (i.e. it showed like your
not working counters, blurred and with a whiteish colour).
The fact that you create slightly bigger files makes me think that you don't actually save them in 8-bit mode; however, if they work nonetheless, all the better! (this reminds me a bit about Chuck Norris' feats, but this is another story

).
Ok, just in case it could help you, here's a detail of an operation of mine. Let's say I want to copy over those counters a little part of the image itself, thus in fact copying and pasting something over. I do it, then click on "File", then "Save". The program at this point tells me that the image has to be exported first, so I choose option b) -> "merge existing layers" (or sthg like that - I'm currently using it in Italian) and then click on "export file". Then, I choose again "File" and "Close". The file at this point is perfectly working!
§ § §
Edit:
As I'm writing, the download links work again (
hope they will even when someone actually tries to download 
).