Hi,
Yes Convertxtodvd is 64 bit compatible, and to Evrac, I suggest contacting the vso support team directly, by clicking on technical support here: http://www.vso-software.fr/support.php

or by posting you log file here (it can be found on your computer by following this path: C:\Documents and Settings\claire\Application Data\Vso, ps you might want to open a new thread for your problem).