can not connect to oracle database in Desktop Testing Testcomplete

Hello,

I'm using this code inorder tp connect to database and do some queries, but it has some difficulties with this connection string, what shall I do??

var AConnection, Driver;
AConnection = ADO.CreateADOConnection();
AConnection.ConnectionString = "Provider=MSDAORA.1;Password=xHl4C06T;User ID=chapar941_Auto;Data Source=srv28;Persist Security Info=True";
AConnection.LoginPrompt = false;
AConnection.Open();
var Driver = DDT.ExcelDriver("C:\\Add_System.xls", "Sheet1");
var k = aqConvert.VarToStr(Driver.Value(0));
var str = "delete from system where system.name like '" + k + "'";
AConnection.Execute_(str);
DDT.CloseDriver(Driver.Name);
AConnection.Close();

I should mention that I can directly connect to PLSQL with this username and password, but via testcomplete is not possible, 

How can I cope with this issue??

Also, this connetcion string is able to connect any other databases

Thanks for your kind consideration