I am a LyX and Ubuntu user. I am trying to use a Greek font named kerkis.
I have installed the needed packages in order to enable xelatex in LyX and Greek language:
texlive-xetex texlive-lang-greek texlive-latex-base texlive-latex-recommended
I enabled the option "Use non tex fonts (via Xetex/LuaTeX)" and in my LaTeX preamble I insert the code in order to use the kerkis font:
\usepackage[T1]{fontenc}
\usepackage{kmath,kerkis}
Although I get an error on LyX. You can see the error on the screeshot:
The error says:
Package polyglossia Error:
Font \zf@basefont="" not loadable: Metric (TFM) file or installed font not fo
seems to be multiple error.

And finally i got my text on pdf without errors!! Thanks guys for your help :)
– ALdaperan Sep 28 '11 at 16:51