error in c# with SQL

Question

Hi all,
I am novice in the c #.
Having completed the Application contains SQL database.
But when I run on another machine gives me an error message as follows:

http://img103.herosh.com/2009/09/02/819895428.jpg

Please note that I have the installation of the .net framework, And the connection string I used is:

SqlConnection cn = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\MyData.mdf;Integrated Security=True;User Instance=True");

Please Help me...