the TNS entry exists, but I'm not using it on OLEDB Provider. I'm using the <IP address>:1521/ORCL syntax (on desktop works and I see it working on other QV Server). There are no firewall issues as I tested the same kind of conection with the following VB script:
Set Conn = CreateObject("ADODB.Connection")
Conn.ConnectionString = "Provider=OraOLEDB.Oracle.1;Password=<clear password>;Persist Security Info=True;User ID=<clear user id>;Data Source=<IP address>:1521/ORCL"
Set RS = Conn.Execute("SELECT * from DUAL")