Hello,
this is not a problem of the previewer but of the software that transforms a document to the preview Flash format. Depending on what software is used and your environment is set up, the procedure to add a font may change. Usually, this is an OpenOffice issue and you need to install additional fonts in a way for OpenOffice to pick up on them. There are a variety of good instructions out on the net. I think the location you indicated is one of the possible installation locations.
Regards
Axel