MediaPlayer .DLL

I put a very simple video player in our application and when we installed it
on one user's machine, we get the error: "Exception EMCIDevice Error in
module DaVinci.exe at {some hex address} MMSystem275. cannot find specified
file.  make sure path and file name are correct."

Is there a .DLL that we need to include with our install to make the Media
Player work?  It appears to work on some computers, and not others.  I have
a MMSYSTEM.DLL in my Windows\system directory, is this the file we need to
include?

Thanks,
Jesse