I ran into this issues the other day at a customer. It has NOTHING to do with WCF services as this was in an RTM environment. What actually is happening is the underlying exception is not being filtering up the stack and therefore a generic applicaiton exception is being thrown, in this case the blog title. This expection could mean anything unfortunately.
What it was for us, was the SQL Server database was not getting created properly. We had already existing mdf and ndf files with the same name as the database we were trying to create. Therefore it would not create the databse and would then return the above error.