Excerpt: Delete the [HKEY_CLASSES_ROOT\.xml] "Content Type"="application/x-xml" registry key mentioned above.Warning: Editing the Windows Registry incorrectly can cause serious problems that may require reinstalling your operating system. Macromedia does not guarantee that problems caused by editing the registry incorrectly can be resolved. Edit the registry at your own risk.
[HKEY_CLASSES_ROOT\.xml] "Content Type"="application/x-xml"
To do so: Start -> Run -> regsvr32.exe msxml3.dll