database connection error

Dears ,

i use the following command to connect to database

$conn = new COM("ADODB.Connection") or die("Cannot start ADO");

//$conn =conn.Open("dbatest") ;

$conn->Open("Provider=MSDAORA.1;Password=apps;User ID=apps;Data Source=dbatest;Persist Security Info=true");

but it produce the following error in my page  :-

PHP Fatal error: Uncaught exception 'com_exception' with message '<b>Source:</b> Microsoft OLE DB Provider for Oracle<br/><b>Description:</b> Oracle client and networking components were not found. These components are supplied by Oracle Corporation and are part of the Oracle Version 7.3.3 or later client software installation.

Provider is unable to function until these components are installed.' in C:\IIS_web\xxar_reciets_v.php:58