Unable to Access Media

I am attempting to access my media files on my computer using DIRECTV.   The DVR is connected to the internet via wireless router &  I can access CinemaPlus without a problem.   I also tested the connection in Setup and all is well.  When I attempt to access my computer thru DIRECTV all is well until I click on the name of my computer and DIRECTV spits out a message "unable to access media".  I do have media sharing turned on in my computer and Widows Media Player is set as the default player.  I am able to access my media  files successfully thru my PS3 as well as My Media on my LG TV.  I contacted DIRECTV technical support and they have no idea as to the problem and suggested I check this forum.  I am running Windows 7 on my computer. 

 Anyone have a resolution?  Thanks....Dave