When you try to stream audio or video from Microsoft Windows Media Services, you may receive an error message that resembles the following in Microsoft Windows Media Player:
The specified protocol is not supported.
Note This problem does not occur when you play content that is stored on a hard disk drive.
When you click the Network tab of the Windows Media Player Options menu, nothing happens.
On the Windows Media Player Network tab, the "Streaming proxy settings" protocol listing is empty.
This problem may occur if any one of the following conditions is true:
The Wmnetmgr.dll file is unregistered.
Note The Wmnetmgr.dll file is located in the C:\Windows\System32 folder.
The Wmsdkns.xml file is corrupted.
Note The file is Windows Media Player's network namespace file.
The Wmsdkns.xml file has incorrect permissions.
To resolve this problem, use one of the following methods.
Register the Wmnetmgr.dll file by using an account that is in the Administrators group. At a command prompt, run the following command.
Make sure that the user account that is using Windows Media Player has Modify permissions for the Wmsdkns.xml file.
Note In Windows Vista, the file is located in the C:\Users\Userame\AppData\Local\Microsoft\Windows Media\11.0 folder. In Windows XP, the file is located in the C:\Documents and Settings\UserName\Local Settings\Application Data\Microsoft\Windows Media\11.0 folder.
Delete the Wmsdkns.xml file. After you delete it, Windows Media Player will re-create the Wmsdkns.xml file.
Steps to reproduce the problem
Unregister the Wmnetmgr.dll file by using an account that is in the Administrators group. At the command prompt, run the following command.
regsvr32 /u wmnetmgr.dll
Make sure that the user account that is using Windows Media Player has Deny permissions for the Wmsdkns.xml file.