#1
Recently my guitar stand was knocked and my Ibanez Acoustic guitar was knocked over on its face. A string broke but the problem there is now a very loud buzzing sound coming from the Nut area when played the first few frets and open string. Any suggestions on how to fix it? (I have a dual action adjusting thing inside the guitar if that helps...i have no idea what it means or does)
#2
You shouldn't adjust anything just yet! You may have cracked the nut itself or loosened it so that it's not firmly glued to guitar anymore!
Have you closely inspected the nut on all visible sides (use magnifying lens)? (cracked??)
Have you removed all strings since or did you just replace the broken string? (loose and nut falls off!!!)
#3
Yeah that sounds like a nut is broken. The strings are probably too close to the neck now and buzzing on the frets. It could have also forced the neck to move to an improper angle, causing fret buzz. Is this a bolt on neck or glued on (set neck)? Probably set neck, but it does make a difference.

If you're pretty good with this kind of thing, you can check it out yourself, a magnifying glass will help a lot. If not, take it to a competent guitar tech, preferably a luthier. It could be the type that's a cross between set and bolt on, bolted internally to a heavy wood block. If so it could have moved the entire block, forcing the neck to an improper angle. Check where the neck and body join, it might have a crack there too.

The adjusting thing inside is probably the truss rod, dual action from what you describe, in this case it might need to be adjusted, have that done by a professional unless you really know what you're doing. I always advise people to avoid adjusting the truss rod themselves, truss rods are easy to break if you are not quite competent with guitar repair, and that is a very expensive repair job, in many cases more than the guitar cost originally. I don't think the truss rod is the main problem here, but could be a secondary issue.

My opinion is take it to a good tech and have it checked out, it sounds like this might be more involved than most people have the knowledge and expertise to handle. without having it in my hands I'm not sure, but it might be more than I would want to tackle...and I know what I'm doing...
Hmmm...I wonder what this button does...