As has been mentioned on the forum before, it recently came up that Vista has disabled much of the Directsound implementation, which means the Directsound object in Construct currently may not work on Vista (I don't have Vista to check right now). It would be useful if someone could tell me what does and doesn't work in Directsound on Vista at the moment.
I'm planning a new audio plugin, using the newer XAudio2 API (which is still part of DirectX), which is supported by Vista (and for the forseeable future, hopefully!!). It's also a much more sophisticated API than Directsound, so I may be able to add better features anyway (arbitrary mixing, channel groups, optimised effects and filters, amplification, etc). I'll start work on it soon, but complete plugins take a bit of time to write, so it may be a while before it appears in a build anyway.