Is it a registry error?
or is it "iTunes had detected an audio configuration problem"
If it is, or if you see a "200 Error" when opening iTunes 7, the suggested fix is that QuickTime may need to be reinstalled.
Follow the steps below to uninstall QuickTime and then download and install QuickTime using the QuickTime standalone Installer.
1. On the Start menu, click Control Panel.
2. Open the Add or Remove Programs control panel and select QuickTime in the list of currently installed programs.
3. Click the Remove button and follow the prompts to remove QuickTime from your computer.
4. Download the QuickTime standalone installer fromhttp://www.apple.com/quicktime/download/win.html
There are two options for downloading QuickTime
select the second option that does not include iTunes.
5. If during the download you choose to run the installer, proceed to the next step.
* If you chose to save the download, double click the QuickTimeInstaller file.
6. Follow the on-screen instructions to install QuickTime.
7. Reopen iTunes.
iTunes 7 or later for Windows Installation stops responding while "registering modules"http://docs.info.apple.com/article.html?artnum=304541