As of December 5th, 2003, (build 10506), this message is a special case of the more general message that a token could not be found. The present message occurs if Q++ cannot find a character that was slated for special formatting, at the end of the textual token conversions of a textbox, just before it starts to apply attributes.
This message is almost always due to the use of a holidays symbol filter(or of the no duplicates options) and informs you of which symbols have been removed by filtering or the use of the no duplicates option. You can usually ignore it, after verifying that the textbox referred to in the message looks OK.