Im not sure how they upload ringtones on a 71xx cause as far as I know u got no "media manager" in your Dm do u? Maybe if u have a media card do it through "my computer" straight onto your media card. If u want to change a ringtone, go to media/ringtones or music/select a song/ hit menu and choose "set as phone tune"
About the only way to load ringtones onto a 7100i is to download them from a website. I think there is something called coolserve.dk tha allows you upload from your computer and then to your phone.