Before every RETURN_FALSE; you should snmp_clse(ss);
A diff against the latest /ext/snmp/snmp.c (1.51) is
available at:
http://www.iol.ie/~padraiga/snmp-1.51-snmpclose.diff
Note this happens a lot in my experience as there is
a lot of code that does:
while (snmpget(...))
{
   ....
}