I experience problems on two Dell Servers with Windows 2012 R2 Essential and SNMP reporting.
We are using SNMP and OpenMange for reporting to Ncentral (monitoring system).
I tested and I know that configuration which I use only doesn't work on Windows 2012 R2 Essential and Dell Servers.
In Event Viewer I found it:
The SNMP Service encountered an error while accessing the registry key SYSTEM\CurrentControlSet\Services\SNMP\Parameters\ExtensionAgents.