BibTeX, biblatex and biber ⇒ Pushing References to LyX using JabRef

[trasc]

So, I'm really, really new at this so be forewarned that I have absolutely no idea what I'm doing. Anyway, I'm trying to use Jabref for references. So basically, what I did, and I have no idea if this is right, is go Insert>Lists & TOC>BibTeX Bibliography>Add and added the .bib file from Jabref. Then I just used the "push to LyX" button in Jabref and the reference showed up in my References section of my document. But when I click the view as PDF button, I get the following error message:

Package natbib error: Bibliography not compatible with author-year
citations.

...mand\NAT@force@numbers{}\NAT@force@numbers

Check the bibliography entries for non-compliant syntax,
or select author-year BibTeX style, e.g. plainnat

Except that I did select plainnat as the style when I added the .bib file.

Also, in the LaTeX log, there's a few lines of code which say

Package natbib Warning: Citation `dspguide' on page 1 undefined on input line 7
9.

[1{/var/lib/texmf/fonts/map/pdftex/updmap/pdftex.map}


]

Package natbib Warning: Citation `dspguide' on page 2 undefined on input line 1
82.


Package natbib Warning: There were undefined citations.

[2

] (./imaging1.aux

Package natbib Warning: Citation(s) may have changed.
(natbib) Rerun to get citations correct.

I'm using Ubuntu by the way.

Any idea what I can do to get this working? Sorry if I seem really new, I have absolutely no idea how LyX/LaTeX works but my lecturer insists I use it for this report.