I was seeing this same error message. Running modprobe ip6_tables would generate the message.
ip6_tables: disagrees about version of symbol xt_compat_match_from_user I had done an apt-get upgrade a while back and it looks like I had not rebooted since that upgrade. I verified this by comparing the uptime to the apt history of when linux-image was last installed. So I was running a different kernel that did not match the modules on the filesystem. I rebooted and everything was fine. I would say this is not a bug. Brian
