Figure out if any of dll files are missing, corrupted or are different from the original. Once you have the correct dll file, simply double-click on it in the dll file browser to install it in the missing dll folder.
Download the DirectX End-User Runtime. You need to be a End-User in Windows 10 for this to be available. This is the same version you should get from the Windows Store if you're installing from it.
It has been fixed by 1 hour ago. You can change the package destination folder in the download tab, click on Apply, and download again. Let's say Sekira: Shadows Die Twice is from the download tab and click on the following link to download it again.
I use SharpDevelop to explore the code in d3d9. I use the version 4.7.3225.0 that you can get from here. If you look at the source, you'll notice that I use hex editor to view the source. If you want to navigate in the code, you can use IHLTAV to navigate the code. If you want to archive the source of the d3dx9.dll file that you are working on, you can use SharpZipLib 1.1.0. Let me know, if you find any other bugs. 7211a4ac4a