Hi, tried both of the last suggestions.... Still same errors. Could it be because my zip contains more then one file ? See , the zip contains these items : - MySetup.msi - setup.exe - "WindowsInstaller3_1" folder (pre - requisite) -"DotNetFX35" folder (another pre-requisite) Now - when i run my SFX on win XP - it does run the "setup.exe", but after checking for the pre-requisites , it fails to run the MSI !!! Here is the log content : The following properties have been set: Property: [AdminUser] = true {boolean} Property: [ProcessorArchitecture] = Intel {string} Property: [VersionNT] = 5.1.3 {version} Running checks for package 'Windows Installer 3.1', phase BuildList The following properties have been set for package 'Windows Installer 3.1': Running checks for command 'WindowsInstaller3_1\WindowsInstaller-KB893803-v2-x86.exe' Result of running operator 'VersionGreaterThanOrEqualTo' on property 'VersionMsi' and value '3.1': true Result of checks for command 'WindowsInstaller3_1\WindowsInstaller-KB893803-v2-x86.exe' is 'Bypass' 'Windows Installer 3.1' RunCheck result: No Install Needed Running checks for package '.NET Framework 3.5', phase BuildList Reading value 'Install' of registry key 'HKLM\Software\Microsoft\NET Framework Setup\NDP\v3.5\1033' Read integer value 1 Setting value '1 {int}' for property 'DotNet35InstallSuccess' The following properties have been set for package '.NET Framework 3.5': Property: [DotNet35InstallSuccess] = 1 {int} Running checks for command 'DotNetFX35\dotNetFx35setup.exe' Result of running operator 'ValueEqualTo' on property 'DotNet35InstallSuccess' and value '1': true Result of checks for command 'DotNetFX35\dotNetFx35setup.exe' is 'Bypass' '.NET Framework 3.5' RunCheck result: No Install Needed Launching Application. Running command 'C:\WINDOWS\system32\msiexec.exe' with arguments ' -I "C:\DOCUME~1\...\LOCALS~1\Temp\7zS909.tmp\MySetup.msi" ' Any ideas ?