Ok two things
1. I just relised that this should really be under "help", sorry
2. I found my problem, under "user interface" the "expert config" option wasn't checked I should be good now.
I am running mumble 1.1.8 on Fedora 10. I am trying to using the Link plugin with ioquake3 (specifically with Quake III and STVOY: Elite Force HM). I have the "mumble-plugins" packaged installed. I tried to enable the plugin but I look under Configure -> Settings and there is no plugins option in any of the tabs.