This is a known problem - it's caused when we get some zero values from the VMware API, and this breaks our metric calculations in the nworks Collector. When we receive these zero values from vCenter, then you see these very high "%" value(s)....
We have a workaround that fixes this in our 5.5 release, due very soon (April/May). Or if you need more assistance right now, please contact email@example.com
Any questions please let us know!