you can fix a fret buzz by sticking some sandpaper under the nut of the buzzing string. the paper lifts the string slightly, which keeps the string off the frets that is is buzzing against. sandpaper is used because it sorta grips the nut.

here's what you do:
1. loosen string
2. put a 1/8 inch strip of medium fine (150 grit) sandpaper under the string, rough side down.
3. tighten the string.
4. cut the excess sandpaper away with a razor blade.


hope this helps.

jon