The Vanco Payment Processor module uses a core file (CRM/Core/BAO/PaymentProcessor.php) in CiviCRM 4.1 that I'm unable to find in CiviCRM 4.4. Does anyone have knowledge of the file and might know if it has been renamed or moved within the file structure?
This was removed before CiviCRM moved to git, so I browsed the old Subversion repo. I can see that revision 44887 removed it. It's present if you click the first link but not the second: http://svn.civicrm.org/civicrm/!svn/bc/44886/trunk/CRM/Core/BAO/ http://svn.civicrm.org/civicrm/!svn/bc/44887/trunk/CRM/Core/BAO/
Both failed with a 503 error, I suspect this is to blame: https://community.bitnami.com/t/varnish-throwing-503-on-svn-requests/25828
So I Googled "civicrm r44887" and found an IRC log:
[08:54] <civi-bot> r44887 by yashodha: CRM-11334 -- https://fisheye2.atlassian.com/changelog/CiviCRM?cs=44887
So there are your answers! Check that atlassian.com link and CRM-11334, you'll find what you're looking for.