InstallScript on Windows 7

Hi ,

I am trying to run a msi in which its installscript is using some functions MessageBox. When I run it on a windows XP, those MessageBox boxes do pop up. There is no problem with it. However, when I run it on a Windows 7, there is no MessageBox pop up? I need the MessageBox to debug my InstallScript. Do you know the problem. Is there any function similar to MessageBox and run well on Windows 7.

Regards