【新手求助】VB使用ADO连接oracle

Module ModDb
Public Const CONSTR As String = "Provider = OraOLEDB.Oracle.1;Persist Security Info=True;Data Source=orcl;User ID=BOOKMAN;PassWord=password"
Private cnn As ADODB.Connection
Public Sub DBConnect()
cnn = New ADODB.Connection
cnn.ConnectionString = CONSTR
cnn.Open()
End Sub
End Module
上面的代码老是执行的cnn.Open()出错困扰了两天了 ADO引用导入了
错误提示为：未找到提供程序。该程序可能未正确安装。