[texhax] BibTex trouble

[Modhurita Mitra]

Hi,
 	I had been using the same .bib file for some time; everything was 
working until I added another entry to the file. Now it doesn't compile, 
saying:

>bibtex filename
This is BibTeX, Version 0.99c (Web2C 7.4.5)
The top-level auxiliary file: filename.aux
I found no \bibdata command---while reading file filename.aux
I found no \bibstyle command---while reading file filename.aux
(There were 2 error messages)
>

What is going wrong?

Thanks,
M