KDE Help Center "Build Search Index" Fails

[Robert Morrison]

On Kubuntu 6.10/KDE 3.5.5, KDE Help Center "Build Search Index" 
function fails with:

Global symbol "$kdekdehtmldir" requires explicit package name 
at /usr/bin/khc_docbookdig.pl line 94.
Execution of /usr/bin/khc_docbookdig.pl aborted due to compilation errors.

Any hints appreciated.