Error in updating my SQL server 2005

I encountered, this message when I updated MySQL Server 2005. I heard that it is better to update my table so I did it. After connecting to the SQL server 2005 instance via a DAC (dedicated administrator connections) this error appears. Any suggestions?

Microsoft SQL Server Management Studio
A connection was successfully established with the server, but then an error occurred during the login process. (Provider: TCP Provider, error: 0-An existing connection was forcibly closed by the remote host.) (Microsoft SQL Server , Error: 10054)
