[Pljava-dev] error compiling pljava source 1.3

Hi!

I have to install pljava in postgresql version 8.2, so I have to compile
pljava from source but when I launch make command this is the response

make[1]: Entering directory
`/usr/share/pljava/pljava-1.3.0/build/classes/pljava'
javah -classpath . -d /usr/share/pljava/pljava-1.3.0/build/jni <jni
classes>
/usr/share/pljava/pljava-1.3.0/build/jni/org/postgresql/pljava/internal/Backend.h:
No such file or directory
make[1]: *** [/usr/share/pljava/pljava-1.3.0/build/jni/.timestamp] Error 1
make[1]: Leaving directory
`/usr/share/pljava/pljava-1.3.0/build/classes/pljava'
make: *** [pljava_all] Error 2

someone can help me to understand where the problem is?
bye