Unable to connect to oracle db

I am getting unspecified error on line Qry1.Open()

Below is the snippet of the code:-

function pdfname() {

var Qry1;

// Create a query

Qry1 = ADO.CreateADOQuery();

// Specify the connection string

Qry1.ConnectionString = "Driver={Microsoft ODBC for Oracle}; CONNECTSTRING=(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=xxxxx)(PORT=xx))(CONNECT_DATA=(SERVICE_NAME=xxxxxxx))); uid=xxxx;pwd=xxxx;";

// Specify the SQL expression

Qry1.SQL = "Select * FROM table1 WHERE comm_code = 'COT'";

// Execute the query

Qry1.Open();

// Process results and insert data into the test log

Qry1.First();

while (!Qry1.EOF) {

Log.Message(Qry1.FieldByName("columnname").Value);

Qry1.Next();

}

// Closes the query

Qry1.Close();

}