this has probably been discussed before so i apologize up front. i am having trouble upgrading my live site for the latest NB. some permission errors with the server. however, a fresh install would not be a problem. would i lose anything if i uninstalled the old version and installed the new version?
Yes, you would most certainly lose everything.
Uninstalling Ninjaboard will remove all Ninjaboard data.
What you can do is delete all the files manually and then install the new version.
Of course be sure to use Akeeba to take a full backup of your website before attempting any of this.