Powerdot problem.

After a long hiatus, I am trying to use powerdot to format slides for a
talk that I am planning to give.

When I tried to process the *.tex file, in the manner that I had used in
the past, I came to a shuddering halt, with a warning:

> %%%% WARNING: Transparency operations ignored - need to use
> -dALLOWPSTRANSPARENCY

and an error:

> Error: /undefined in .setopacityalpha

The error is followed by an "Operand stack", an "Execution stack" and
a "Dictionary stack" which are (in my current state of ignorance)
meaningless to me.

I have attached a file "demo.tex" to illustrate the problem.  I
attempted to process this file, using the following steps (which worked
in the past --- like two or three years ago):

    latex demo
    dvips demo
    ps2pdf demo.ps

The first two commands evince no problems (as far as I can tell,)  The
last command produces the warning and error referred to above.

I am running Ubuntu 22.04, with a Mate 1.26.0 desktop.

Can anyone rescue me?  Thanks.

cheers,

Rolf Turner

-- 
Honorary Research Fellow
Department of Statistics
University of Auckland
Stats. Dep't. (secretaries) phone:
         +64-9-373-7599 ext. 89622
Home phone: +64-9-480-4619

\documentclass[
size=12pt,
paper=screen,
mode=present,
display=slides,
style=tycja,
fleqn,
]{powerdot}
%
\title{A load of dingoes' kidneys}
\author{Rolf Turner}
\date{\today}
\begin{document}
\maketitle

%------------------------------------------------------------------------
\begin{slide}{Introduction}
\begin{itemize}
\item Mumbo, jumbo, rhubarb, rhubarb.
\end{itemize}
\end{slide}
%------------------------------------------------------------------------

\end{document}