Hi Thanks for your help. Just for the record, and to help others, I fixed the problem. In this case at least I encountered the following error messages: env LANG=C /usr/bin/mrtg /etc/mrtg/mrtg.cfg Unknown SNMP var ssCpuRawUser.0 at /usr/bin/mrtg line 1678 Unknown SNMP var ssCpuRawUser.0 at /usr/bin/mrtg line 1678 WARNING: Expected a number but got '102 days, 0:09:38' WARNING: Expected a number but got 'server' Unknown SNMP var ssCpuRawSystem.0 at /usr/bin/mrtg line 1678 Unknown SNMP var ssCpuRawSystem.0 at /usr/bin/mrtg line 1678 WARNING: Expected a number but got '102 days, 0:09:38' WARNING: Expected a number but got 'server' Unknown SNMP var ssCpuRawNice.0 at /usr/bin/mrtg line 1678 Unknown SNMP var ssCpuRawNice.0 at /usr/bin/mrtg line 1678 WARNING: Expected a number but got '102 days, 0:09:38' WARNING: Expected a number but got 'server' ERROR: Target[server.cpu][_IN_] ' $$target[11]{$mode} + $$target[12]{$mode} + $$target[13]{$mode} ' (warn): Use of uninitialized value in addition (+) at (eval 59) line 1. ERROR: Target[server.cpu][_OUT_] ' $$target[11]{$mode} + $$target[12]{$mode} + $$target[13]{$mode} ' (warn): Use of uninitialized value in addition (+) at (eval 60) line 1. WARNING: Skipping Update of server.cpu, inlast is not defined WARNING: Skipping Update of server.cpu, outlast is not defined To fix this I added the lines: LoadMIBs: /usr/share/snmp/mibs/UCD-SNMP-MIB.txt LoadMIBs: /usr/share/snmp/mibs/HOST-RESOURCES-MIB.txt LoadMIBs: /usr/share/snmp/mibs/HOST-RESOURCES-TYPES.txt Here's my config: Target[serverload]:ssCpuRawUser.0&ssCpuRawSystem.0:string@server Directory[serverload]: server MaxBytes[serverload]: 100 Title[serverload]: CPU LOAD on server PageTop[serverload]: <H1>CPU (user and system) Load %</H1> Unscaled[serverload]: ymwd ShortLegend[serverload]: % YLegend[serverload]: CPU Utilization Legend1[serverload]: User CPU in % (Load) Legend2[serverload]: System CPU in % (Load) Legend3[serverload]: Legend4[serverload]: LegendI[serverload]: User LegendO[serverload]: System Options[serverload]: growright,nopercent Hope this helps someone. Dan