I am having the same issue as in the post here:
http://www.fusioncharts.com/forum/FindPost11480.aspx
Extra text insterted into the page. From the follow ups it appears to be due to the fact we are using JSF 1.2.
I have started porting the code to JSF 1.2, but have not done a JSF component before and its taking some time. If you have a JSF 1.2 jar that would help.