I decided I should improve my contact with the upstream developers and subscribed to some mailing lists. I have to work out what is going on on the PA-RISC port regarding Ghostscript. Somehow the ps2pdf tool is failing on the doxygen documentation. I confirmed that the problem persists with my preview package of the 6.51 upstream version.
The idea that the Postscript file generated on PA-RISC is wrong was disproved by copying the .ps file to my local i386 machine and converting it with ps2pdf which went without a problem. So the Ghostscript interpreter seems to be defect on PA-RISC.
Hmpf, seems like the python-gtk packages does not install anymore in Debian unstable. Looks like the interface of the compileall script in python-base was changed. Do not have the time now to check, this will have to wait for tomorrow.