While setting up a new NSX 6.2.2 / vCenter 6.0u3 lab, I was receiving the following error (in vSphere) when trying to install NSX VIBs under "Host Preparation":
"XXX eam.agent.enable.label not found XXX"
For my environment I had not (yet) installed Update Manager so it *should* have connected directly.
I ended up deploying VUM as a test, but still failed.
Eventually figured out that I had not set DNS server entries on the ESXi hosts - since when I installed ESXi, I did not yet have AD/DNS VM built...
So, if you find this page, verify you can resolve the vCenter by name from your ESXi hosts...
Brian