(Needless to say that I didn't manage to make hikebike work; it's commented out in renderd.conf.)
The reason were missing fonts which River packaged (as TSandroid-fonts) and installed, plus the segfaulting mapnik 0.7.1, and renderd needing a few minutes to get its final speed (needing about ten reloads with the default timeout for the first tile). We are getting there.
Cheers Colin