Con la tua bibliografia e il mio biber otengo questo log (main.blg)`[1] Config.pm:425> INFO – This is Biber 1.7
[1] Config.pm:428> INFO – Logfile is 'main.blg'
[656] biber-darwin:252> INFO – === Thu Aug 29, 2013, 19:32:34
[657] Biber.pm:333> INFO – Reading 'main.bcf'
[855] Biber.pm:607> INFO – Using all citekeys in bib section 0
[1005] Biber.pm:2997> INFO – Processing section 0
[1120] Biber.pm:3134> INFO – Looking for bibtex format file 'mybibliography.bib' for section 0
[1139] bibtex.pm:911> INFO – Decoding LaTeX character macros into UTF-8
[1151] bibtex.pm:786> INFO – Found BibTeX data source 'mybibliography.bib'
[1711] Biber.pm:2883> INFO – Overriding locale 'en_US.UTF-8' default tailoring 'variable = shifted' with 'variable = non-ignorable'
[1711] Biber.pm:2889> INFO – Sorting 'entry' list 'ydnt' keys
[1711] Biber.pm:2893> INFO – No sort tailoring available for locale 'en_US.UTF-8'
[1979] bbl.pm:479> INFO – Writing 'main.bbl' with encoding 'UTF-8'
[1987] bbl.pm:552> INFO – Output to main.bbl`
Confrontandolo col tuo direi che hai una versione di biber obsoleta; cose che capitano con MiKTeX, purtroppo.
Aggiorna biber con il tuo package manager, quello di MiKTeX.