$ biber ff527
INFO - This is Biber 1.5
INFO - Logfile is 'ff527.blg'
INFO - Reading 'ff527.bcf'
WARN - Warning: Found biblatex control file version 2.6, expected version 2.3
INFO - Using all citekeys in bib section 0
Use of uninitialized value $llabel in concatenation (.) or string at /usr/lib/perl5/vendor_perl/5.14/Biber.pm line 664.
Use of uninitialized value in string eq at /usr/lib/perl5/vendor_perl/5.14/Biber/SortLists.pm line 77.
INFO - Processing section 0
INFO - Looking for bibtex format file 'test.bib' for section 0