" or one of its dependencies."
Most likely this is the VC++ runtime dependency.
For PDFNet versions 7.0 and older, this is the VC++ 2010 runtimes. Starting with PDFNet 7.1 it is now the VC++ 2013 runtimes.
https://www.pdftron.com/documentation/windows/info/prerequisites/#net-framework-40+
Please download the installer from MS and install on the target system, or add to your installer/deployment system to automate.