When I upgraded to the latest scansnap version (2.1L11) there is no longer any integration with DTPO 1.5. I recently also upgraded to Leopard and upgraded scansnap just to be sure I had compatible software.
When I bring up the scannap settings the Application tab is greyed out!
We are aware of this. The solution for now is to remove the preferences of the ScanSnap Manager and handle it manually. They are found in this file: home folder > Library > Preferences > jp.co.pfu.ScanSnap.V10L10.plist