BibTeX, biblatex and biber ⇒ .bib file path (using BibLaTeX)

[monamipierrot]

Hello,
I successfully use BibLaTeX for my thesis in LyX under WinXP
I never had any problem when working in the LyX environment.
The problem is when I try to compile a simple .tex file (with LaTeX, and outside LyX) with BibLaTeX bibliography (or the LyX-LaTeX export, which always work fine): in the 1st LaTeX run it can't locate my .bib file resulting in citing just the labels and a blank bibliography. I tried to rename it, to change directory, to put the file in the MiKTeX folder (above all the bibtex)... Nothing. (The MikTeX path contains spaces... don't know if it's a problem.)
The absurd thing is that biblatex find the bib file ALWAYS if run in LyX.
You probably want to know WHY do I need this if I can compile perfectly with LyX.
It's because at the final touch of my Thesis, I will need to run some more tex parsers such as lilypond-book and so on which can't still be used automatically in LyX. And, of course, for debugging purposes...
I found out that this problem is an old one in forums but I couldn't find a solution.
Please help!

[josephwright]

The first run never will. You need to do latex then bibtex then latex (with biblatex) to get your citation data.

[monamipierrot]

The first run never will. You need to do latex then bibtex then latex (with biblatex) to get your citation data.

Yes I know. Nothing. It doesn't find the file. Simply this.