You could try this.
Select any mp3 file and get info on it. In the get info window, select "Open with application" in the drop down menu and make sure iTunes 2.0.2 is selected. If not, change it to iTunes 2.0.2. Then click the button that says "Change All..." to make sure that all mp3 files will be associated with iTunes 2.0.2.
Also.. go to your QuickTime preferences under your System Preferences and under the "Plug-In" tab, click the button at the bottom that says "MIME settings..." From here, make sure that the MP3 check box is unchecked so QuickTime isn't changing association of MP3 files at all.
Good luck : ]