to backup the contacts, you can use PIM Backup.
http://forum.xda-developers.com/showthread.php?t=299705
I think I know how to fix the problem though...
I know you can change the sound your phone makes when you press the end key. I have a vista sound there...
Try this. I'm not sure that it will fix it, but its worth a try. Go to your windows directory, and delete the file Midi2Wave_079_4098.wav. You may need to unhide the ROM files and use a third party file explorer to delete it. If delete doesnt work, just cut and paste it somewhere else