mtpro seems to produce \notin symbols where the upper left part separated by the slash is filled in black. See

It happens in dvi and ps and pdf output.
The input code is very simple:
\documentclass{article}
\usepackage{mtpro}
\begin{document}
$\notin$
\end{document}
and a run through latex:
...
(/usr/share/texmf-texlive/tex/latex/base/article.cls
Document Class: article 2004/02/16 v1.4f Standard LaTeX document class
(/usr/share/texmf-texlive/tex/latex/base/size10.clo))
(/usr/local/share/texmf/tex/latex/pctex/mtpro.sty) (./test.aux)
(/usr/local/share/texmf/tex/latex/pctex/mpy1mtt.fd)
(/usr/local/share/texmf/tex/latex/pctex/mpy2mtt.fd)
(/usr/local/share/texmf/tex/latex/pctex/mpy3mtt.fd) [1] (./test.aux) )
Output written on test.dvi (1 page, 260 bytes).
mtpro.sty is 2004/09/14 v4.0
and the font mtsyt says:
/version(1.000)readonly def
/Notice(Copyright (C) Publish or Perish, Inc. 2000-2004.)readonly def
Thanks a lot for any comment/suggestion!
Best wishes
Norbert