In snmp-graph.properties we define two reports:

report.cisco.buffhits.name=Buffer Hits Percentages (Cisco)
report.cisco.buffhits.columns=bufferSmHit, bufferMdHit, bufferBgHit, bufferLgHit, bufferHgHit

and

report.cisco.buffmiss.name=Buffer Misses (Cisco)
report.cisco.buffmiss.columns=bufferSmMiss, bufferMdMiss, bufferBgMiss, bufferLgMiss, bufferHgMiss

but those columns do not exist in datacollection-config.xml.