to use the new Meetings Plugin. I installed the latest nightly build of Openfire on my debian 7 system.
After that i installed the Meetings Plugin and in the Admin-Interface I could (if I want) change options for Meetings. So the Plugin was correctly installed.
I experience the same error. The openfire nightly builds from Feb 03 2015 worked. I tried the nightly build from Feb 06 2015 onwards and I get the 404 error.