If you receive the subject error when you start the Windows XP Media Player, it is possible that some 3rd party application registered an incorrect version of the wmpui.dll.

To resolve this issue:

1. Open a CMD prompt and type:

regsvr32 %SystemRoot%\system32\wmpui.dll.

2. When you receive DllRegisterServer in <Expanded %SystemRoot%>\system32\wmpui.dll succeeded, press OK.

3. Start Windows Media Player.