Hi
I have the same problem with russian characters.
May I explain:
In admin preview chart showing with right russian characters, but on the joomla frontend russian characters showing not in right encoding. I use joomla 1.5 version.
What I can say else, when I open .xml file from /administrator/components/com_artiofusioncharts/cache in notepad++ and format it in utf-8 and resave it, in fronpage all show ok, but if I save again chart in admin panel, characters broke again. I think its cause .xml files saving by script in utf-8 without BOM.
Please help. Thank you! and sorry for bad english.
P.S. four days working about this problem and nothing...any solutions exist?