TC 6.2 x86
the snmp.so needs libnetsnmp.so.15, however the Net-SNMP contains libnetsnmp.so.30
PHP 5.4.3 is not supporting Net-SNMP 5.7.2, so PHP needs to be upgraded or Net-SNMP needs to be downgraded.
I did downgrading Net-SNMP , it was not good choice, because it needs openssl-0.9.8 instead of 1.0.1.