Help sought regarding use of GraphViz on Windoes

I have used graphviz on Unix. I need now to be able to use it on Windows Server 2008 R2.

I have executed the msi and the bits are on the drive.

I open up a powershell console.

I execute

& "C:\Program Files (x86)\Graphviz2.39\bin\dot.exe" -Tpdf > may.pdf

I am in the folder where exists.

A may.pdf file is created.

When I attempt to open it, I get an error message saying that the file is damaged.

So, that appears to be out.

I then try

& "C:\Program Files (x86)\Graphviz2.39\bin\dot.exe" -Tsvg > may.svg

A file is created.
I attempt to launch the file, and a new tab opens in my web browser.

Nothing is ever displayed.

This is much easier on Unix - it just works.

Can someone familiar with using GraphViz on Windows help me figure out how to do this?
Thank you.

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