pantarhei,
Your registry entries should look like this:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\CLSID\{implementing guid}]
@="MyMediaStatusSinkAssembly.MediaStatusSink"
[HKEY_CLASSES_ROOT\CLSID\{implementing guid}\Implemented Categories]
[HKEY_CLASSES_ROOT\CLSID\{implementing guid}\Implemented Categories\{62C8FE65-4EBB-45e7-B440-6E39B2CDBF29}]
@="Media Status Sink"
[HKEY_CLASSES_ROOT\CLSID\{implementing guid}\Implemented Categories\{FCB0C2A3-9747-4c95-9d02-820AFEDEF13F}]
[HKEY_CLASSES_ROOT\CLSID\{implementing guid}\InprocServer32]
@="mscoree.dll"
"ThreadingModel"="Both"
"Class"="MyMediaStatusSinkAssembly.MediaStatusSink"
"Assembly"="MyMediaStatusSinkAssembly, Version=x.0.0.0, Culture=neutral, PublicKeyToken=xxxxxxxxx"
"RuntimeVersion"="v2.0.50727"
[HKEY_CLASSES_ROOT\CLSID\{implementing guid}\InprocServer32\3.5.0.0]
"Class"="MyMediaStatusSinkAssembly.MediaStatusSink"
"Assembly"="MyMediaStatusSinkAssembly, Version=x.0.0.0, Culture=neutral, PublicKeyToken=xxxxxxxxxx"
"RuntimeVersion"="v2.0.50727"
[HKEY_CLASSES_ROOT\CLSID\{implementing guid}\ProgId]
@="MyMediaStatusSinkAssembly.MediaStatusSink"
Where "{implementing guid}" is the one you've used in your COM visible class, "MyMediaStatusSinkAssembly" is your assembly in the GAC, and MyMediaStatusSinkAssemlby.MediaStatusSink is the class implementing IMediaStatusSink.
Make sure the version numbers and public key token are also correct, and your assembly is in the GAC or it won't load.
Cheers,
Andrew