I do have D3DX9_43.dll in both System32 and SysWOW64.
Last things in my log are Opening USB, Opening FW and Opening DEV9, I rewrited it here because I can't copy anything from my log when there's a crash window.
04-05-2015, 01:30 AM (This post was last modified: 04-05-2015, 01:36 AM by willkuer.)
sorry dunno.
"Directx Setup An internal system error occurred" is probably the key to your solution. I just googled a bit and found like 10 different solutions. Maybe you can have a look by yourself and try some of them. Most refer to missing file access either due to usage or due to missing administrator rights for the dx installer.
Edit:
Obvious solution would be to make a 'clean reboot' and run the installer with explicit administrator rights.