[biblio] TeXworks failing to recognize bib file

[Karl Berry]

    Package biblatex Warning: No "backend" specified, using Biber backend. 
    To use BibTeX, load biblatex with the "backend=bibtex" option.

I don't know much about biblatex, but it sounds like you need to add
that arg to your \usepackage line, as in:

\usepackage[style=apa,backend=bibtex]{biblatex}

(Or use biber instead of bibtex.)

Hope it helps,
Karl