New apacite package (2012-Feb-14) problem?

Question

A new version of the apacite package was introduced on 2012-Feb-14, with three added options to select different citation commands: apaciteclassic, natbibapa, and nocitation. I installed the package on MiKTeX 2.9 and tried to use it. The apaciteclassic option works without any issues. However, when I try natbibapa I get this error (I paste part of the log):

("C:\Program Files (x86)\MiKTeX 2.9\tex\latex\natbib\natbib.sty"
Package: natbib 2010/09/13 8.31b (PWD, AO)
\bibhang=\skip48
\bibsep=\skip49
LaTeX Info: Redefining \cite on input line 694.
\c@NAT@ctr=\count89
)
LaTeX Info: Redefining \BBA on input line 3.
! Undefined control sequence.
\apacite.sty-h@@k ...elist {\orig@mb@citenamelist 
                                                  ,citeauthort,citeauthorp,c...
l.3
?
! Emergency stop.
\apacite.sty-h@@k ...elist {\orig@mb@citenamelist 
 ,citeauthort,citeauthorp,c...
l.3 
End of file on the terminal!

Here is a minimal working example (that produces the error):

\documentclass[12pt]{report}
\usepackage[natbibapa]{apacite}

\begin{document}

Lorem ipsum dolor sit amet. \citet{shermis1999comparison} consectetur adipiscing elit.

\bibliographystyle{apacite}
\bibliography{myrefs}
\end{document}

And here is the bib entry:

@ARTICLE{shermis1999comparison,
author = {Shermis, M.D. and Lombard, D.},
title = {A comparison of survey data collected by regular mail and electronic   mail questionnaires},
 journal = {Journal of Business and Psychology},
year = {1999},
volume = {14},
pages = {341--354},
number = {2},
publisher = {Springer}
}  

Can someone install the new package and see whether he/she gets the same error while utilizing the natbibapa option? Is there something I am doing wrong?

I appreciate any help.

Answer 1

It's quite unclear what apacite.sty does on lines 1966-1994.

It defines a command \@mb@citenamelist under the assumption that the classic option has been specified; for the natbibapa option it says

\if@APAC@natbib@apa
\AtEndOfPackage{%
\let\orig@mb@citenamelist\@mb@citenamelist
\edef\@mb@citenamelist{%
  \orig@mb@citenamelist,%
  citeauthort,citeauthorp,citefullauthort,citefullauthorp,Citeauthort,%
  <...other strings...>
}
}
\fi

but \@mb@citenamelist is not defined, so the whole thing fails. One conjecture is that the option natbibapa should augment the list, so saying

\makeatletter
\def\@mb@citenamelist{%
  cite,fullcite,shortcite,citeNP,fullciteNP,shortciteNP,%
  citeA,fullciteA,shortciteA,citeauthor,fullciteauthor,shortciteauthor,%
  citeauthorNP,fullciteauthorNP,shortciteauthorNP,%
  citeyear,citeyearNP,nocite,nocitemeta,%
  maskcite,maskfullcite,maskshortcite,maskciteNP,maskfullciteNP,%
  maskshortciteNP,maskciteA,maskfullciteA,maskshortciteA,%
  maskciteauthor,maskfullciteauthor,maskshortciteauthor,%
  maskciteauthorNP,maskfullciteauthorNP,maskshortciteauthorNP,%
  maskciteauthorA,maskfullciteauthorA,maskshortciteauthorA,%
  maskciteyear,maskciteyearNP,masknocite%
}
\makeatother

before loading apacite.sty would cure the problem.

A second possibility is that the list provided for the natbibapa option is exhaustive and in this case adding

\makeatletter\def\@mb@citenamelist{}\makeatother

before loading apacite would be the provisional solution.

Of course this is something that should be brought to attention to the developers of apacite.