| I agree with scrodzilla, you don't want to file that fret.
Be really careful when you tap that fret down though, mellowgerman.
Tapping the fret can definitely fix the problem, don't get me wrong.
But, if you tap it too hard, it can end up being lower than all the other frets, thus perpetuating more buzz.
Conversely, if you don't tap it firmly enough (or you tap the fret with the neck resting on a spongy or springy surface) and it doesn't seat, the spurs of the fret could possibly damage/widen the fret slot just enough so that the fret won't stick in by itself.
Sorry, don't mean to scare you here.
If tapping the fret doesn't work (or you are at all apprehensive about tapping in the fret) I would strongly recommend getting Dan Erlewine's book Fret Work Step-by-Step (good call GeoffByrne). It's a pretty short read, and you could even just use it as a reference. That book will give you really detailed accounts of the various ways to fix problems like this, and it will also point out how to avoid potential pitfalls.
If you don't end up getting the book, you might want to at least read the free info about tapping in frets on stewmac.com.
Good luck, let us know how it turns out! | 
