software

I received my Agile 2000 last week. Pretty amazing guitar considering that I got it on sale for 99.99 instead of the regular 199.99. I actually paid the price of an SX.

Playability is identical to the 2500 I had before, it looks as though I'm playing the same neck... with one annoying exception: there's a fret buzz on the D string. There are some minor buzz around the neck if I put the action very low, which I expect of course, but the D string is really buzzing a lot, and even more so in the first 4-5 frets. Since this buzzing seems to affect only one string, I suspect that maybe the D slot of the nut is too low... does it make sense?

This is a graphite nut, so I don't really know how to correct that...

What should I do before going to a tech or changing the nut? Any other thing I should look for?

Thanks.