what do you want to get rid of?...a tracker?...trackers are good when it comes to torrents...they keep all the information you're DL'ng or UL'ng together. they sort of act like a tunnel that connects the seeders to the downloader so the information knows where it needs to go. the changes in your firewall were probably to allow access to your computer through frostwire. some firewalls won't allow torrents through, so those settings need to be changed.
***EDIT
can i ask what exactly you downloaded? music? movie? program/app? in order to get rid of frostwire tracker, you'll need to uninstall and delete frostwire....when you installed frostwire is when the changes to your firewall would've been made. the tracker itself isn't a threat, it's needed for any torrent program to operate properly. did you download and install a program and then the changes were made?