Shoutbox

Follow the following steps and it should correct the error.

Click Start
Click Control Panel (You may need to click Settings first)
On the left pane click Switch to Classic View
Doubleclick Administrative Tools
Doubleclick Microsoft .NET Framework 1.1 Wizards
From the Wizard select "Trust an assembly"
On the next screen of the wizard select "Make changes to this computer" and click "Next"
On the next screen click "Browse" and brose for the exe file "MessengerCountDown.exe" Once you have selected the proper path click "Next"
On the next screen scroll the slider to the top giving the application Full Trust. Once you have done this click "Next"
Click Finish

Now try and run the program you shouldn't have any troubles doing so now.