Apologies for the delay. I still haven’t been able to reproduce this image on a Windows XP virtual machine.
It looks like the problem could be specific to your machine, especially since the error is happening in System.Windows.Form and not in System Ninja code.
Is your Microsoft .NET Framework installation up to date? It may also be worth running Microsoft’s .NET Repair tool to make sure there aren’t any problems.
Secondly, have you tried a complete uninstall and re-install of System Ninja?