C++ Builder 5 and DirectX

Playing wave files through DirectX in Builder 4 use to work. Under Builder 5
the CreatSoundBuffer() API returns with a DSERR_INVALIDPARAM.
I am running NT4 with service pack 5 and assume it has DirectX3.0, however
the Microsoft support say you should have Dxdiag.exe and Dsetup.dll
installed but I cannot find them.
If you attempt to find the version using DirectXSetupGetVersion() you need
the Dsetup.dll.
Does anyone know how I should debug the problem and whether its worth trying
to find what version of DirectX my system has?