Like rich text editors? i have downloaded every add-on with similar description but they look just like this text box; text only, no images no hot links...
I cant tell without a login to your forum but before you do anything else i'd recommend you change the folder to your forum to either just vanilla or forum or something.
You'd be best just installing it there in the first place. It's possible to change the settings but it's a bit tricky and if you cant get extensions going I wouldnt like to place bets how successfully you'd be able to do it.
is this an already-in-action forum? What I meant was to delete the folder /vanilla/ and the MySQL db, and start fresh w/ a new db, but in the root directory.
Might I also suggest that you investigate your roles and permissions settings pages to make sure the correct roles have the correct permissions for any new extensions.