To remove it, add to /etc/modprobe.conf:
# No IPv6
install ipv6 /bin/true
install ip6_tables /bin/true
install ip6table_filter /bin/true
In /etc/hosts, comment out (or remove) this line:
::1 localhost6.localdomain6 localhost6
That is the only way to disable ipv6, and you have to reboot after making those changes. You don't need
the ip6 tables lines, but they'll get loaded anyways and just waste memory otherwise. Or they did as I seem to recall which is why I have them.
If, however, the kde programs are hardcoded to probe and attempt to connect via ipv6
anyways, this won't help you. I don't have kde installed right now to tell if this is an actual
problem or not.