Accessing pureftpd using Firefox

I have setup a server running pureftpd and all is fine when uploading and downloading using Internet Explorer. However, when I click on a file that should start to download using Firefox a window opens up and it looks like Realplayer is trying to start or something like that. I can't figure out what is going on. I don't even know if it is a Firefox issue of pureftpd. If anyone has run into this problem, how did you correct it? Thanks as always, Aaron