New user and MRTG error help

[Paul Baxter <ppabaxte@xxxxxxxxxxxxxx>]

Does anyone know what this warning means, the interface is working I'm 
using it now.

WARNING: Problem with External get '/usr/bin/monthlystats eth0':
  Expected a Number for 'in' but got '*'

WARNING: Problem with Externale get '/usr/bin/monthlystats eth0':
  Expected a Number for 'out' but got '* ERROR: Interface is down, 
aborting'

ERROR: Target[host-eth0][_IN_] ' $$target[0]{$mode} ' did not eval into 
defined data
ERROR: Target[host-eth0][_OUT_] ' $$target[0]{$mode} ' did not eval into 
defined data
WARNING: Skipping Update of host-eth0, inlast is not defined
WARNING: Skipping Update of host-eth0, outlast is not defined

If you can help you will be doing me a huge service.
Regards
Paul Baxter