Fatal Error while installing new msi

[AKNG]

Hello everyone,

I use installAware 9 to create an installer for my software and recently, I got a problem when I try install the old version of my software over the new one (for example: I tried to install version 5.0 over version 5.1), I got a popup with a message "Fatal Error". This message never pop up at the same moment during the installation and there is no more information than the message "Fatal Error". And when I go to C:\Documents and Settings\All Users\Application Data, to look for the folder where the files are extracted, and it seem like not all the files are extracted.

if anyone know how to solve the problem, please help!

Note: Both version 5.0 and 5.1 were installed fine and they work perfectly on a PC which never install the software before. And this problem did not happen with version 4.1 and 5.0


Thank you