I'm using IA9 Studio and have been banging my head over registry access for hours. I was testing on Windows Server 2008 and my installer creates a key under HKLM\\Software... but although the installer completes successfully, the registry key doesn't get created. I'm logged in as domain admin so I don't think it is a security permissions issue. I can manually create the key just fine.
I finally gave up and tested on my Windows 7 desktop and it works fine.
It could be permissions .... what access is the MSI Exec itself being ran under?
Is it 64-bit by any chance? If so, check the virtualisation (InstallAware is a 32-bit application so gets virtualised, and you will need to put the install into 64-bit mode).
Actually, that one line broke the entire install. It says it is successful but no files are copied. All I did was add a line to set it to native 64-bit mode.