mrtg error in linux

[root@2222]# mrtg start

this error apper

ERROR: Mrtg will most likely not work properly when the environment variable LANG is set to UTF-8. Please run mrtg in an environment where this is not the case. Try the following command to start:

env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg

[root@2222]# env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg after type the above command following error appear

ERROR: Target[mrtg_373][IN] ' $target->[2]{$mode} ' evaluated to 'NaN' instead of a number ERROR: Target[mrtg_374][IN] ' $target->[3]{$mode} ' evaluated to 'NaN' instead of a number

help me