LyX 1.44: Questionmarks instead of citations

[Rainer M. Krug]

Hi

I know that it has been asked before, but I can't find it. So there it 
is again:

I am having problems with bibtex. I can insert the citations in lyx 
without problems, but when I run pdflatex, I get questionmarks insted of 
the references in the text and no bibliography. In addition, the LaTeX 
log says:


Package natbib Warning: Citation `Myers2000a' on page 5 undefined on 
input line
 82.


Package natbib Warning: Citation `Harper1977' on page 5 undefined on 
input line
 84.


for each reference.

I get the same when I run BibTeX directly but no other error messages.


Any ideas welcome,

Rainer