[pdftex] Undefined control sequence: \MPxoffset

[Joe Riel]

I have written a small document class, based on letter.cls,
for typesetting memos for my company.  On the first page 
there is a (crude) metapost graphic of the company logo.

In particular circumstances pdfLaTeX fails to compile 
this file while LaTeX works fine.  The error messages in the log file
indicate that \MPxoffset and friends (\MPyoffset, etc)
are undefined at that point.  I am now able to recreate the problem
using 
letter.cls with a short preamble that redefines \opening and
\ps at firstpage to insert the graphic.

If I convert the .mps file to a .pdf then this error doesn't occur.
Any idea why pdfLaTeX fails with the .mps file?
I am using pdfTeX, Version 3.14159-14f-released-20000525 (Web2c 7.3.2x).

Thanks,

Joe Riel

Here is the minimal file:
-------------------------
\documentclass{letter}
\usepackage{graphics}
\makeatletter
\def\ps at firstpage{%
  \def\@oddhead{%
    \raisebox{-0.1in}[0in]{\makebox[1.6in][r]{%
        \resizebox*{!}{1in}{\includegraphics{inceplogo.mps}}}}}}%
  \def\@oddfoot{\mbox{\hb at xt@\textwidth{\small}}}%
\renewcommand*{\opening}[1]{%
   \thispagestyle{firstpage}%
   \vspace*{2\parskip}%
     #1\par\nobreak}%
\makeatother
\begin{document}
\begin{letter}{}
\opening{}
\fbox{\raisebox{0pt}[6in]{}}
\begin{verbatim}
Adjust number of lines (and height of preceding fbox)
so that a page break occurs in the middle of this
verbatim environment.
1
2
3
4
5
6
7
8
9
\end{verbatim}
\end{letter}
\end{document}



Here is the metapost logo file inceplogo.mps:
---------------------------------------------
%!PS
%%BoundingBox: 0 -63 353 115 
%%Creator: MetaPost
%%CreationDate: 2000.12.19:1251
%%Pages: 1
%%EndProlog
%%Page: 1 1
 0 0.33846 0.24615 setrgbcolor 0 0.00996
 dtransform truncate idtransform setlinewidth pop [] 0 setdash 1
setlinejoin
 10 setmiterlimit
newpath 0 0 moveto
23.39978 0 lineto
23.39978 86.39978 lineto
0 86.39978 lineto
 closepath
gsave fill grestore stroke
 0.69539 0.60924 0 setrgbcolor
newpath 0 90.89978 moveto
23.39978 90.89978 lineto
23.39978 114.29956 lineto
0 114.29956 lineto
 closepath
gsave fill grestore stroke
 0 0.33846 0.24615 setrgbcolor
newpath 31.31982 0 moveto
31.31982 86.39978 lineto
70.92004 43.19989 lineto
54.7196 43.19989 lineto
54.7196 0 lineto
 closepath
gsave fill grestore stroke
newpath 110.52026 86.39978 moveto
110.52026 0 lineto
70.92004 43.19989 lineto
87.12048 43.19989 lineto
87.12048 86.39978 lineto
 closepath
gsave fill grestore stroke
newpath 191.15991 0 moveto
150.84023 0 lineto
131.64027 5.59998 118.4403 23.19994 118.4403 43.19989 curveto
118.4403 63.19984 131.64027 80.7998 150.84023 86.39978 curveto
191.15991 86.39978 lineto
191.15991 63 lineto
150.84023 63 lineto
145.12166 58.00932 141.84009 50.78995 141.84009 43.19989 curveto
141.84009 35.60983 145.12166 28.39046 150.84023 23.39978 curveto
191.15991 23.39978 lineto
 closepath
gsave fill grestore stroke
newpath 199.07996 0 moveto
271.79956 0 lineto
271.79956 23.39978 lineto
199.07996 23.39978 lineto
 closepath
gsave fill grestore stroke
 0.69539 0.60924 0 setrgbcolor
newpath 199.07996 31.5 moveto
271.79956 31.5 lineto
271.79956 54.89978 lineto
199.07996 54.89978 lineto
 closepath
gsave fill grestore stroke
 0 0.33846 0.24615 setrgbcolor
newpath 199.07996 63 moveto
271.79956 63 lineto
271.79956 86.39978 lineto
199.07996 86.39978 lineto
 closepath
gsave fill grestore stroke
newpath 279.7196 0 moveto
320.03929 0 lineto
339.23924 5.59998 352.43921 23.19994 352.43921 43.19989 curveto
352.43921 63.19984 339.23924 80.7998 320.03929 86.39978 curveto
279.7196 86.39978 lineto
279.7196 63 lineto
320.03929 63 lineto
325.75786 58.00932 329.03943 50.78995 329.03943 43.19989 curveto
329.03943 35.60983 325.75786 28.39046 320.03929 23.39978 curveto
279.7196 23.39978 lineto
 closepath
gsave fill grestore stroke
newpath 279.7196 -62.1003 moveto
303.11938 -62.1003 lineto
303.11938 -4.5 lineto
279.7196 -4.5 lineto
 closepath
gsave fill grestore stroke
showpage
%%EOF