Install Sun Java Advanced Imaging (JAI)
Assuming you have installed the the standard Debian package for Sun's JDK,
i.e. sun-java5-jdk, download most recent version of JAI, e.g.
jai-1_1_3-lib-linux-i586-jdk.bin 
and save as /tmp/jai-1_1_3-lib-linux-i586-jdk.bin from
Sun's JAI download
page. Then:
chmod u+x /tmp/jai-1_1_3-lib-linux-i586-jdk.bin cd /usr/lib/jvm/java-1.5.0-sun /tmp/jai-1_1_3-lib-linux-i586-jdk.bin
That's all.
Just Installed Debian, got me sun-java6-jdk via apt and downloaded + chmoded the jai-1_1_3-lib-linux-i586-jdk.bin.
Now when I try to execute the binary from my /usr/lib/jvm/java-1.5.0-gcj-4.6 or /usr/lib/jvm/java-6-sun I get the error message "This is not a proper JDK directory. Exiting install."
Already tried setting the JAVA_HOME to those folders and tried installing the JRE installer for JAI as well.
Any ideas?