I have installed this plug in on 2 different jenkins instances, both running 1.6.17

One instance worked perfectly, the other one says it installed correctly and it shows in the installed plugins on the admin page, but the "Trigger builds remotely (e.g., from scripts)" option is not showing under Build triggers.

Any suggestion on how to diagnose why this is the case?

I've looked at the Jenkins logs and the only mention of this plug in is that it installed correctly. I've reinstalled it a few times and even used the .hpi method with the same results.