Wow old thread! What screw are you talking about? The two bolts close to the fender are pretty straightforward. The one on the tube with the maf just needs to be loosened. It's a metal clamp so just loosen it enough to pull the airbox out.
2006 330i | TiAg/Black Leather | Steptronic | Premium Package | Cold Weather Package | iPod Interface Adapter | Clear Bra | Window Tint (35%)