If you bought the game from Ageod, why do you need steam for?
Anyway searched in my laptop and have that file besides in Windows/SysWOW64
Both files share the name, but the size is different.
1,9 Mb for the 64 bits
2,28 Mb, 32 bits
I do not know which file needs steam, so IMO better update directx from Microsoft instead of putting the file manually.