Portmap, NFS and sandbox problem

Hi
I receive these errors in system log, periodically.
kernel[0]: portmap 57 FS READDATA SBF /private/etc/hosts.allow 13 (seatbelt)
portmap[57]: warning: cannot open /etc/hosts.allow: Permission denied
kernel[0]: portmap 57 FS READDATA SBF /private/etc/hosts.deny 13 (seatbelt)
portmap[57]: warning: cannot open /etc/hosts.deny: Permission denied

And also when I use internet sharing and connect a client nfs connection is disconnected and I receive these in system log:

com.apple.DirectoryServices[11]: clnttcp_create: RPC: Port mapper failure - RPC: Timed out
natd[3405]: failed to write packet back (Host is down)
natd[3405]: failed to write packet back (No route to host)
natd[3405]: failed to write packet back (Host is down)