I already install this two requirement:
1-Connector/Net 6.8.1 beta or higher version to check the Connector/Net & Entity Framework features. (download at: http://dev.mys
That's because Visual Studio Express does not allow you to install extensions. This is one of the limitations of the Express edition. You need to add everything MySQL related manually.
This is also stated here:
MySQL for Visual Studio does not support Express versions of Microsoft development products, including the Visual Studio and the Microsoft Visual Web Developer.
To use MySQL Connector/Net with an Express versions of Microsoft development products, use MySQL Connector/Net 6.7.4 or later, without installing the MySQL for Visual Studio.
That does not mean that you cannot use MySQL in the Express Edition. It just means that you don't get to use the nifty design-time tools ;-)