TS 6.5 Search: enabling incremental updates

System

TS 6.5 for windows. I moved index and search to a different windows server from TS 6.5. When I initiately installed the index and search components, I chose to not to enable incremental updates. Now I want to enable it. In my search.properties file, I have

java.naming.provider.url=tcp://my_ts65_host:3035/
iw.index.events.enable=true

And the index server is restarted fine. However, it does not respond to any TeamSite submit events automatically. If I run the iwndxrefreshbr -i CLT, it will put request into the incremental queue and re-index the newly submitted files.

Can anyone tell me what I'm missing here?