strange error that prevents google maps from appearing if more than 1 column in sql database?

I have 2 sql tables

Artist - ArtistId -p-k
Location  locationId -pk

the following query  fetches data from SQL database and shows a GOOGLE map on .ASPX page with markers

If there is only 1 entry in Artist database it works- The moment more entries are inserted to database table Artists - the
google map stops appearing?

is this an error in the SELECT Clause?




  public string ConvertDataTabletoString()     {        string strcon = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;         //create new sqlconnection and connection to database by using connection string from web.config file         SqlConnection con = new SqlConnection(strcon); ...