did you configure "snmp-server enable" prior to trying to configure these lines ? GSS won't take any snmp config unless you do.
I had a similar issue that turned out to be software versions. I can't remember what version we where on 3.x, but I upgraded to 3.1(1) and snmp works fine. A "sh snmp" didn't return any output (or maybe just that it's enabled) where as now I get screens worth.
you will run into it with 3.1.0 fixed in 3.1.1. Are you running 3.1.0 ?
upgraded the software version from Version 3.1(0) to Version 3.1(2).
The isssue of SNMP got resolved after the upgrade