myfile.tex
mybib.bib
/build [all copiled files go here, including myfile.aux and myfile-blx.bib]

addbibresource{mybib.bib}

bibdata{myfile-blx,mybib}

bibtex8 --wolfgang build/%

bibdata{build/myfile-blx,mybib}

documentclass[a4paper, fontsize=12pt]{scrartcl}
usepackage{filecontents}
begin{filecontents}{mybib.bib}
% This file was created with JabRef 2.8.1.
% Encoding: ISO8859_1

@ARTICLE{author2010,
  author = {Some Author},
  title = {Fancy Title},
  journal = {Another Journal},
  year = {2010},
  volume = {91},
  pages = {229-261},
  number = {2},
  timestamp = {2012.09.01}
}

@comment{jabref-meta: selector_review:}

@comment{jabref-meta: selector_publisher:}

@comment{jabref-meta: selector_author:}

@comment{jabref-meta: selector_journal:}

@comment{jabref-meta: selector_keywords:}
end{filecontents}

usepackage[T1]{fontenc}
usepackage[utf8]{inputenc}
usepackage[ngerman]{babel}

usepackage{csquotes}
usepackage[backend=bibtex8,bibencoding=latin1]{biblatex}
addbibresource{mybib.bib}

begin{document}

section{Section}
Lots of text.
footnote[111]{cite[S.~250--255]{author2010}}

printbibliography

end{document}

The 8-bit codepage and sorting file: 88591lat.csf
The top-level auxiliary file: build/myfile.aux
The style file: biblatex.bst
I couldn't open database file myfile-blx.bib
---line 4 of file build/myfile.aux
 : bibdata{myfile-blx
 :                    ,mybib}
I'm skipping whatever remains of this command