error while building docs

[Kai Habel]

With the current cvs I get an error during the doc-build.

gawk -f ./mkcontrib.awk ./contributors.in > contributors.texi-t
contributors.texi is unchanged
make[3]: *** Keine Regel vorhanden, um das Target »interpft.png«,
  benötigt von »HTML/interpft.png«, zu erstellen.  Schluss.
make[3]: Leaving directory `/home/kai/cvs-octave/octave/doc/interpreter'
make[2]: *** [interpreter] Fehler 2
make[2]: Leaving directory `/home/kai/cvs-octave/octave/doc'
make[1]: *** [doc] Fehler 2
make[1]: Leaving directory `/home/kai/cvs-octave/octave'
make: *** [all] Fehler 2

Sorry it is in german, but there seems to be a problem with "interpft.png"
**No rule to build target »interpft.png«

Kai