Today I was trying to get an old Silverlight application up and running again. I was moving the old site collection to a new database and tried to run the webpart. Of course it failed. I tried to place a new Silverlight webpart and embedd the application. Unfortunately I wasn't able to see the "Media & Content" area within the webparts section.
So... what should you do now? There are two ways on how to handle this problem.
1) Im' working with a migrated SharePoint 2007 site collection and someone forgot to upgrade the visuals. So ran this command:
$site = Get-SPSite http://SITE
$site | Get-SPWeb -limit all | ForEach-Object{ $_.UIVersion = 4; $_.UIVersionConfigurationEnabled = $false; $_.update();}
2) The script did not work? Don't worry! The second way, also the easier one, would be to activate the "SharePoint Server Publishing Infrastructure".
One of the two solutions should bring back the Media & Content area.