OK I have read the FAQ on the Bibletime website and according to it I You have to install an unicode font like Code2000, Arial Unicode MS or
Bitstream Cyberbit to display the special unicode characters.
I can find none of the fonts mentioned in the example amongst the available fonts in debian, and I have many fonts available including ttf-unifont, nifont, xfonts-iunifont, the Libertine O family of fonts and many others.
I have tried by configuring Bibletime to use some of these fonts, but that did not resolve the problem.