This happens because the quote character you use are not supported in the used character set. The solution is to use the utf-8 characterset with eZ publish.
You'll make my day if you give me an easy trick to add/tweek/modify the char converters to deal with the few extra windows characters (the quotes, euro symbols... the usual guilties) and convert them to their proper iso-8859-1 (15) equivalent ?
cf this doc for a more complete description: http://www.cs.tut.fi/~jkorpela/www/windows-chars.html
By the way, I've had the problem with these chars even with utf-8 charset.
