They're each about 25MB, so unable to attach. I uploaded one to my Dropbox though:
http://dl.dropbox.com/u/16249938/Fin...C%20Comics.cbz
In a bit more testing, here's what I've found:
Each file is a CBR with dozens of JPGs under that folder. I extracted it out and created it as a CBZ and tested that, and it also failed.
I then just zipped up the JPGs themselves, without the parent folder, and made that into a CBZ. That worked for one of the comics, but failed for the next few.
I tried a conversion through ComicToEpub, and then brought that output into Calibre, which works.