[OS X TeX] bibtex capitalizatioin

[Paul Bailey]

Hi,

I am getting titles to capitalize as they are in my bibtex files, not  
fixed like bibtex usually does. Here is a demo input file

------- start file.ltx =-----
\documentclass[11pt]{article}
\usepackage[round]{natbib}
\usepackage{aer}
\usepackage{aertt}
\usepackage{ulem}
\begin{document}
Hi, \cite{ur1}
\bibliography{ur}{}
\bibliographystyle{aer}

\end{document}
------- end file.ltx =-----

and bib file
------- start ur.bib =-----
@Book{ur1,
author    = "A. B. Dude and C.D. McDude and J. LaHood",
title     = "SeRious titLe",
publisher = "Publisher",
year      =  2011,
}
------- end ur.bib =-----


Then in the pdf I get "Dude, A. B., C.D. McDude, and J. LaHood,  
SeRious titLe, Publisher, 2011. " Notice how the title is "SeR..." and  
not "Ser"

What gives? For years I've relied on Bibtex to fix my caps in these  
files!

Thanks in advance

oh and
------------
$ pdflatex --version
pdfTeX 3.1415926-1.40.10-2.2 (TeX Live 2009)
kpathsea version 5.0.0
[snip]
$ bibtex --version
BibTeX 0.99c (TeX Live 2009)
kpathsea version 5.0.0
[snip]
-----------

Paul