During installation of VS9, I encountered this same error on several of the audio files. Some it complained about during the installation, others "appeared" to install ok.
When I go to the Audio/Auto Music tab, I get another error message saying "Please insert the SmartSound Library CD "Full Spectrum 22K" .
If you have QuickTime 7 on your system, you'll need to uninstall it, then install the SmartSound files. Then go to http://www.smartsound.com/support/updates.html to get the update for QuickTracks (for compatibility with QT7). After that you should be able to reinstall QT7.
There should be a folder that contains your SmartDownload packs. Go to C:\Program Files\Ulead Systems\Ulead VideoStudio 9.0\SmartDownload and you'll see it there. I recommend that you make a disk backup of all the SmartDownloads and the update packs as well so should you need to ever reinstall you'll have everything already.