"The wave files [are] with correct filenames for Altiverb (version 5 and up)."
Also there's a comment:
"For Altiverb you should use the provided Altiverb folder structures, with the weird 1.1.wav etc file names…"
That means there is a way to name the IRs so that Altiverb can find them.
It's probably worth checking if you have any IRs that are not showing up.