[pstricks] Clash between pstricks, pst-pdf, tabularx, and threeparttable

[Alan Ristow]

Hi all,

I have a document that began producing a rather mysterious error 
yesterday. I have boiled it down to a minimal example (see below), and 
as far as I can tell pstricks is the only thing in the \usepackage list 
that has been updated since the last time I successfully compiled the 
document. However, at this point I am stuck.

When I compile the example with pdflatex I have no problems at all. 
However, the regular latex run that would be required to process my 
graphics via pst-pdf produces:

! Missing } inserted.
<inserted text>
                 }
l.16   \end{tabularx}

(Obviously, my real document contains graphics, though they are not 
relevant to the problem and therefore absent from the minimal example.) 
Compilation works fine for threeparttable environments enclosing regular 
tabulars, and for tabularx environments outside of threeparttable -- 
it's only when threeparttable encloses tabularx that the problem arises.

Thanks for your help.

Alan


\documentclass{minimal}
\usepackage{threeparttable}
\usepackage{tabularx}
\usepackage{pstricks}%
\usepackage{pst-pdf}%

\listfiles

\begin{document}

\begin{threeparttable}
   \begin{tabularx}{3in}{XX}
     1 & 2\tnote{a}\\
     3 & 4\\
     5 & 6
   \end{tabularx}
   \begin{tablenotes}
   \item[a] Hi
   \end{tablenotes}
\end{threeparttable}

\end{document}


  *File List*
  minimal.cls    2001/05/25 Standard LaTeX minimal class
threeparttable.sty    2003/06/13  v 3.0
tabularx.sty    1999/01/07 v2.07 `tabularx' package (DPC)
    array.sty    2005/08/23 v2.4b Tabular extension package (FMi)
pstricks.sty    2008/01/22 v0.36 LaTeX wrapper for `PSTricks' (RN,HV)
pstricks.tex    2008/01/01 v1.20 `PSTricks' (tvz)
   xcolor.sty    2007/01/21 v2.11 LaTeX color extensions (UK)
    color.cfg    2007/01/18 v1.5 color configuration of teTeX/TeXLive
    dvips.def    1999/02/16 v3.0i Driver-dependant file (DPC,SPQR)
  pst-pdf.sty    2007/06/04 v1.1p PS graphics for pdfLaTeX (RN,HjG)
graphicx.sty    1999/02/16 v1.0f Enhanced LaTeX Graphics (DPC,SPQR)
   keyval.sty    1999/03/16 v1.13 key=value parser (DPC)
graphics.sty    2006/02/20 v1.0o Standard LaTeX Graphics (DPC,SPQR)
     trig.sty    1999/03/16 v1.09 sin cos tan (DPC)
graphics.cfg    2007/01/18 v1.5 graphics configuration of teTeX/TeXLive
  preview.sty    2006/08/25 11.84 (AUCTeX/preview-latex)
prtightpage.def
   pdftex.def    2007/06/12 v0.04h Graphics/color for pdfTeX
  ***********