I do not understand if you actually want to use biblatex/biber or traditional bibtex. If the latter, make sure your bibliography processor in Tools > Settings > Output > LaTeX or at least in Document > Settings > Bibliography is "bibtex" or "bibtex8". If you want to use biblatex instead, first read this: http://wiki.lyx.org/BibTeX/Biblatex
HTH Jürgen
