I'm using vb6 and oracle10g express edition
then i've drawn a ADO ctl on form then right click ->properies-> and natural flow as directed there then click test connection but it gives above provider initilise error
This sounds to me like a database connection problem, and not specifically VB. You might find more help by asking about it in the Oracle forum too.
Make sure you include the exact wording of the error message. The sort of details you are putting in the properties for the connection are likely to be useful, as well.