permission denied on key

["Gr., F." <frgroccia@xxxxxxxxx>]

Hi,
I've just noticed the following warning in the /var/log/boot file:

"
Sun Oct 23 10:35:26 2011: error: permission denied on key
'net.ipv4.conf.all.mc_forwarding'

Sun Oct 23 10:35:26 2011: error:
permission denied on key 'net.ipv4.conf.default.mc_forwarding'
"

What does it mean?