Which ones? Those with suffix .tar.gz or .tgz or both? Both are gzipped tars. can you try both 'tar ztvf' and also without 'z' on the 'broken' file? Maybe your browser silently decompresses gzip files? Just tried and both work fine for me with Firefox on XP and Ubuntu 6.10. Will try also on device but I think I already tried many times since it is easier to get them directly from web if one has freshly flashed firmware and no ssh server on device.