Not sure if Plugable have managed to fix this for you, but there should be another debug file in the c:\program files\displaylink core software\debug directory, which is a log from the compatibility check.
This log file will tell us exactly what caused the failure, but depending on what the USB graphics software was, these articles should help:
http://www.displaylink.com/support/ticket.php?id=358
http://www.displaylink.com/support/ticket.php?id=359
Wim