collector shell !snmpget space characters?

Not to be that guy, but while the string is technically an octet string so can contain any ASCII(?) characters. But the vendor usually has restrictions and going with the most restrictive will give the best compatibility. Cisco usually limits to alphanumerics, hyphens, and underscores (spaces not supported). I'm sure you would change it if you could, but I don't think LM considered the possibility that you could have spaces in your community string. 

You could log onto the collector directly and issue snmpget that way, assuming a useful OS like Linux. It would at least validate connectivity.