I resolved the issue at hand w/ the following. I think the version of the client I was using did not support the volume checks
removed the NSCLient++ - 0.3.5.1 agent
reinstalled the NSCLient++ - 0.3.9.1 agent
completed the nsc.ini file
and used the following command to check volumes
./check_nrpe -H xx.xx.xx.xx -p 5666 -c CheckDriveSize -a Drive=h:\\$ARG2$ MaxWarnUsed=85% MaxCritUsed=90%
and the results are as follows
OK: All drives within bounds.|'h:\data01 %'=71%;85;90 'h:\data01'=158.22GB;187;198;0;220
Thanks for the help with resolving the issue