In this post I was bemoaning the fact that to access the event log from Yukon resident managed code requires the containing assembly to be loaded into the UNSAFE CAS bucket whereas I thought the EXTERNAL_ACCESS one should be enough. I've just had it confirmed that this is a bug, the EventLogPermission was accidently omitted from the EXTERNAL_ACCESS permission set. It will be fixed in the public beta, beta 2.
Incidently, if you have no idea of what I'm talking about, have a look at CLR Architecture chapter of our book which is posted here on TheServerSide .NET for public review. It goes into how the Code Access Security envionment is set up in Yukon.