You can use binary build from the site: https://www.netxms.org/download/agent_packages/nxagent-1.2.5-aix.tar.gz
Upgrade package to install thru management console is here: https://www.netxms.org/download/agent_packages/nxagent-1.2.5-aix.apkg
These binaries are build on AIX 5.3 and should run fine on 6.1.
