I have the eval version 3.0.6 on my computer and I am trying to get a logo to appear.
I placed the logo in the folder where Fusion Charts is and where my page is just to make sure the path is not the issue.
Just using a part of your sample.
chart logoURL='logo.gif' caption='Monthly Unit Sales' ...
* Also the palleteColor param seems to not work either. There is a work around for this though with the color tag on each data item.