As the title says, there is no map available for exclusion on the “Versus” tab.
might have a connection problem with the bnet server, or your local data might be corrupted/messed up. Try backing up and deleting your \Documents\Warcraft III folder.
Tried doing that, the game launched as if I’ve never played it (showed me the initial cutscene and all) but the bug remained the same, unfortunately.
I’m not sure then, I can only assure you that I have the map veto lists as normal here. =\