As MIkeWalsh explains here, viewtopic.php?p=43806#p43806
"Debian are in the process of changing .debs over to a new compression standard. The installed Puppy 'dpkg-deb' is built to work with the old standard, and no longer works with the new one. Extraction techniques for .deb packages, all across the web, recommend 'ar' as the first thing to try.
Now; Puppy has access to the 'ar' utility, but you don't install it from the PPM or a .pet package. It's part of 'binutils', which in turn is part of the devX SFS package that comes with every Pup. So the way to get access to the 'ar' utility is to load your devX first....."
If Mike's right, that's an inconvenient way to go about the not infrequent task of making use of a debian deb. I would think that a couple of small pets (maybe only one) would return recent Ubuntu and debian binary-compatible Puppys to their respective former 'binary-compatible' status.