I was trying to create external content type using SharePoint Designer and got error message after installation of beta 2 and can not create external content type using SPD.
1) Start BCS service on server farm if it is stopped. [SharePoint Central Administration -> Services on Server]
2) Now you will need to create BCS service for your web application.
[SharePoint Central Administration -> Application Management -> Manage Service Application -> Create New BCS Service.]
3) Now check it through SharePoint Designer, It should work.
Hope this will help.