The object missing errors are js and are a warning given to you by your browser. Do you see any issues with the display or data, or are you experiencing any errors in the admin other than these warnings?
For the XML message you are getting when you get to the failure page you will need to view the page source to get at the xml, if you have any problems determining what the error is post back with the xml from this page minus any sensitive details.
The fact that the direct pay full request and response are blank tells me that you are only accessing the Express Checkout like you have configured it.
