Gem snmp has some problem.

< ^ > P N |<>|^_>< --- | ~ ...Help

When I got some information from a device using SNMP::Manager#walk, it 
reported this error after got some data.
	/var/lib/gems/1.8/gems/snmp-1.0.2/lib/snmp/manager.rb:239:in 
`get_next': host xxxx not responding (SNMP::RequestTimeout)
But, when I used snmpwalk tool, everything was OK.