I don't see any reason for Repository pattern to NOT work with Entity Framework.  Repository pattern is an abstraction layer you put on your data access layer. Your data access layer can be anything from pure ADO.NET stored procedures to Entity Framework or an XML file. 

In large systems, where you have data coming from different sources (database/ XML /Web service), It is good to have an abstraction layer. Repository pattern works well in this scenario. I do not believe Entity framework is enough abstractive to hide what is going behind the scene.

I have used Repository pattern with Entity Framework as my data access layer method and am yet to face a problem.