on the confirm page, how is the oid being generated:
$LinkPointAPI_itemized = "transactiondetails->oid";
$LinkPointAPI_itemized = "".session_id() ."";
usually, it should use the session_id()
if it is using the session_id() already, make sure that the session id is working correctly.
Create a new page and add the following code:
open this page in fire fox, then again in IE and compare the ID's, they should be different.