Cannot load SCTP module with IPv6 disabled

Issue

• Cannot load SCTP module with IPv6 disabled
• We found that with ipv6.disable=1 added to the kernel boot line in grub.conf sctp.ko would not load.
  Changing ipv6.disable=1 to ipv6.disable=0, sctp module get loaded properly and sctp connections are also established.
• Is the ipv6 module required by the sctp module even if the system has no IPv6 IP addresses configured?
• Loading sctp module fails:

# modprobe sctp
FATAL: Error inserting sctp (/lib/modules/2.6.32-...el6.x86_64/kernel/net/sctp/sctp.ko): Unknown symbol in module, or unknown parameter (see dmesg)

# dmesg
sctp: Unknown symbol compat_ipv6_setsockopt
sctp: Unknown symbol inet6_bind
sctp: Unknown symbol inet6_unregister_protosw
sctp: Unknown symbol in6_dev_finish_destroy
sctp: Unknown symbol ipv6_setsockopt
sctp: Unknown symbol inet6_ioctl
sctp: Unknown symbol unregister_inet6addr_notifier
sctp: Unknown symbol inet6_getname
sctp: Unknown symbol ip6_xmit
sctp: Unknown symbol inet6_register_protosw
sctp: Unknown symbol icmpv6_err_convert
sctp: Unknown symbol inet6_release
sctp: Unknown symbol register_inet6addr_notifier
sctp: Unknown symbol compat_ipv6_getsockopt
sctp: Unknown symbol ipv6_chk_addr
sctp: Unknown symbol ipv6_getsockopt
sctp: Unknown symbol ip6_dst_lookup