Open WMP 10 from your start menu.  go to tools/options then click on the
'about' button.  It should tell you the specific version # you have.  It
looks like this update is a bit old, and likely you are running a higher
version than .10.0.0.3934, or 11.0.0.4354.

Current USA XP is higher than 10.0.0.3934, for WMP
and on Vista, it is version  11.0.0.6x.

I am going to take a guess if you ever go to windowsupdate.microsoft.com,
you should have a later version, and shouldn't need to specifically install
this patch, as it's already been installed.

Are you having the symtoms that this KB addresses?

http://support.microsoft.com/default.aspx/kb/902344