One of the characters in a CD-Text field on your master CD is causing this issue.
CD-Text can typically only display generic text, so letters with accents or umlauts will probably not display properly if used.
This can usually be corrected by deleting all of the CD-Text that was imported during the Copy CD step and re-entering it in the Master Uploader App, making sure to not use any 'special' characters. Creating a new master CD with no CD-Text encoded and copying that into the Master Uploader App is another option.