Application Manager monitoring tool

How to perfectly add hosts in application manager for monitoring with 'snmp' protocol(with proper snmp configuration)?. I could add hosts with 'ssh'/'telnet' protocols but when I try to add with snmp it was giving errors and I could not remember the error.

From serverfault

• In order to monitor anything with SNMP, the target has to have a working SNMP service. Under Windows and also under most Linux distros, the SNMP service is not installed by default. You first need to install it, then configure it.

  : I have it installed and running but the error was something saying that the snmp is not configured to allow the app. manager to monitor the specified host.

  : I'm using zabbix for monitoring multiple resources and found this tool difficult to monitor application and databases. On my research I found "Application Manager" on www.manageengine.com site. I installed it and found it having to monitoring all kind of system resources. But my confusion is, on this site I saw two more tools something like "Network management" and "server Management" and could not decide which one would be the best tools for monitoring all kind of system resources. I only tried 'application manager' tool. How about the remaining two tools?.

  wolfgangsz : I don't know any of them. I use nagios to monitor all our servers and switches. In order for SNMP to work, the client and the server have to use the same community name (if you use version 2c, otherwise same credentials) and the server has to be configured to allow queries from the client's IP address. There are a lot of possible reasonhs why this won't work, way more than I can explain here without you giving specific details of what the error message is.
  From wolfgangsz