This actually sounds a little like a compilation-type discussion for this type of file. I would almost put it in Game Discussion, but if you plan on creating a compilation of solutions for this particular issue, I think Tutorials might be a best fit for this.
Just remember, Help boards are for people who are asking for help-- but you can refer any of those who need it to a Tutorial link.
Moving to Member-Made Tutorials, and editing title to "How To Fix Your d3dx9 File" so it will match the new section a bit better.
(If you have any objections, though, PM me and we'll get it sorted out for you. ^^")