On the releases page, a release is required which contains a .zip file whose filename ends with -bc, -bcc, or -wrath. For example, this release from LeatrixMaps has a release named Leatrix_Maps-3.0.00-wrath.zip.

CEnsusPlusWotlk should create a release which contains a file like the following:

CensusPlusWotlk-wotlk.zip

Strange, it still gives me an error but by the looks of it you've done everything right. It does allow me to install it which is better than before. Perhaps it is -wotlk ? Not completely sure.

I would just use the wowinterface source for wowup, its up there and loading in wowup for me

It should be getting picked up via wow interface since its listed there now as well from what i understand, but i'll put out another release for that instance.

This should now be showing correctly in wowup

Strange, it still gives me an error but by the looks of it you've done everything right. It does allow me to install it which is better than before. Perhaps it is -wotlk ? Not completely sure.