Just spotted this over on BoardGameGeek -
www.boardgamegeek.com/thread/546004/bon-card-errata-now-available-on-nexus-website
"From Nexus Website
A number of small errors appear in some unit cards of the first print run of Battles of Napoleon - The Eagle and the Lion, which become relevant when certain optional rules are used. An Event/Reaction card (#53) also included an error in the "reaction" part of its game text"
The link on the Nexus games site, which also has a link to the .pdf for the revised cards, is http://www.nexusgames.com/read.asp?id=3714 (for some reason trying to paste that in to this message as a url loses the ?id=3714, which makes it pretty useless!), and FFG have already posted over in the BoardgameGeek thread how to get the replacement cards in the US.