The Windham Portfolio Advisor is a Windows-based application. To run the WPA on your own Mac, you will need to set up a Windows virtual machine. The most common solution available is through Parallels.
Install Parallels on your Mac computer
Install a licensed copy of Microsoft Windows on the Parallels localized virtual machine
Install the WPA
The most common cause for this error is an incomplete (interrupted) installation of a prerequisite, the Matlab Compiler Runtime. Follow the instructions to manually install the Matlab Compiler Runtime and restart the WPA.