OK, I have been running into this issue too. Unfortunately, I've misplaced my manual (which has the serial number), so reinstalling wasn't an option at the moment (I would need to dig through a bunch of storage boxes), but I did find a way around this.
In the Political Machine 2008 folder, there is the PM2008_Launcher.exe (which the desktop and menu shortcut goes to) and the PolMachine2008.exe file. I deleted my shortcut, and then made a shortcut for the PolMachine2008.exe file on the desktop.
The game is now launching fine, and I can once again play those very fun 'old scenarios' that came with Political Machine 2008!
Hopefully, if anyone else is having this issue, this resolves it! Hope this helps!