A100ST

I just downloaded from a US mirror and installed the game. When I go to open it I got this UDK.exe system error saying the program cant start because D3DCOMPILER_43.dll is missing from my computer. It advises me to try reinstalling to fix the problem which I did once. I also cannot join a server from the launcher; probably because of this error. Did I do something wrong in the download/install process?