snmp interfaces problem

[newww]

hi
we are just new to snmp
we need it to work with mrtg
we have installed net_snmp packages but when we run the command
snmpgetnext -c public -v 1 localhost interfaces
we obtain the next message
HOST-RESOURCES-MIB::hrSystemUptime.0 = Timeticks: (866215) 2:24:22.15
and in the
/var/spool/mail/root
we find
retries: 5
backoff: 1)
at /usr/bin//../lib/mrtg2/SNMP_util.pm line 486
SNMPGET Problem for ifInOctets.2 ifOutOctets.2 sysUptime sysName on public@10.0.11.200::::::v4only
at /usr/bin/mrtg line 1798
ERROR: Target[10.0.11.200.2][_IN_] ' $target->[0]{$mode} ' did not eval into defined data
ERROR: Target[10.0.11.200.2][_OUT_] ' $target->[0]{$mode} ' did not eval into defined data
WARNING: Skipping Update of 10.0.11.200.2, inlast is not defined
WARNING: Skipping Update of 10.0.11.200.2, outlast is not defined


we don't understand what's the problem
thanks for helping us