Hi,
With the explanation given in
http://xml.apache.org/fop/graphics.html#packages
I download JAI on a PC with windows XP.
Then I put jai_codec.jar and jai_core.jar in the lib directory.
 
D:\DATA\apache\apache-forrest-0.7\lib\optional\jai_codec.jar
D:\DATA\apache\apache-forrest-0.7\lib\optional\jai_core.jar

Then when I display the pdf file from the "samples"/usemap page
no image can be found in the PDF file.

Has somebody the same problem, and already found a solution.

Paul