This is a problem lots of people have been having, me included. I don't think this is a well known fix for it so here it is:
-Go to the settings tab on the XMB.
-Select the Network Settings option.
-Now disable the Media Servers.
This will disable the option under the XMB tabs 'Picture' 'Music' and 'Video' to search for Media Servers and also stop this error when downloading game updates.