No, the error you are getting is due to Java not able to find your CA. I never ran into this running on RHEL 6 and 7, so my guess is logstash looks at a specific location that doesn't exist on AIX (since it was never tested on AIX). You might be able to hack it by adding this argument to your logstash init.d file
-Djavax.net.ssl.trustStore
If this was my env, I would switch to Linux and call it a day. 