Hi and thanks for your post. It sounds like you are almost all set up.
From reading your note, the first thing I would check would be your managed nodes. You should ensure that the various servers that you are managing have SNMP configured to forward traps to the OME server. I think this process is discussed in the OME Tutorial section (first time setup). Once you configure the managed node, you should see the traps show up in the Alert console.
Hope this helps,
Rob