Hi John,
QuickApps for SharePoint 6.0 has built in web parts logging.
The messages are logged to the ULS log files, they're logged using the the product name "QuickApps for SharePoint" and the log level is High. In order to see the messages your SharePoint logging has to be enabled and the level to be set so the level High events are logged.
There is no setting that would enable/disable the logging, it's always on.
This is how log entry looks like using the ULSViewer (http://archive.msdn.microsoft.com/ULSViewer) and filtered by the product name.
Please let me know if you still have any questions.
Thanks,
