The 2950 is not listed in the support matrix for OpenManage Enterprise. I'll link to it below. The 11G platform is the oldest platform supported at this time. I would confirm that the iDRACs on your R610s are on the latest available firmware. You may also want to use something like netstat to make sure all the correct ports are open. You can find them on page 23 of the manual for OMEnt. [URL] [URL]
I'm setting up a new instance of OME 3.1 and tried the auto discover. It found my all R710's but none of the R610's or 2950's. I installed OMSA on a few of these and used the OMSA login credentials when setting up the discovery in the WSMAN/Redfish filed and also in the IPMI field and each time the discovery failed.  Also tried adding SNMP but failed as well.   Is there a certain way to setup OME to talk to these older systems? 
OME not identifying PE 2950 or PE R610