C# and oracle database connection problem

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C#

Oracle

database

connection

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hi guys, i need to connect to oracle database with c# application trough tunnel,
with the tunnel, in the connection string i need to connect to localhost:9090, but whatever i try to connect the application is trowing error at connection.Open(); function.

usings:

using Oracle.DataAccess.Client; 
using Oracle.DataAccess.Types;

ERROR:

An unhandled exception of type 'Oracle.DataAccess.Client.OracleException' occurred in Oracle.DataAccess.dll

Additional information: External component has thrown an exception.

the code is:

string DBC = "User Id=SCHEMANAMEHERE;Password=PASSHERE;Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=9090))(CONNECT_DATA=(SID=orcl)));";
            Oracle.DataAccess.Client.OracleConnection conn = new Oracle.DataAccess.Client.OracleConnection(DBC);
            Oracle.DataAccess.Client.OracleCommand cmd = new Oracle.DataAccess.Client.OracleCommand();

            try
            {
                conn.Open();
            }
            catch (OracleTypeException ex) { System.Windows.Forms.MessageBox.Show("ERROR: " + ex.Message); }
            cmd = new Oracle.DataAccess.Client.OracleCommand(" select * from KLIENT;", conn);
            cmd.ExecuteNonQuery();

on conn.open the application is trowing unhandled exception which i cant catch with Exception, OracleExcpetion, OracleTypeException ... so what should i do?! i need this app very fast to finish but im still strugiling with this problem for about 2 days now....
thanks in advance.