Okay, that title was a trick. The fact is you can’t read the log files created from a pure InstallScript installation.
In Basic MSI and InstallScript MSI installations, you can look at the installation and uninstallation log files, because they are just text files. This is not the case with pure InstallScript logs. You have to send the log file to InstallShield tech support and they will deciper it for you.
Here is a Knowledge Base article on the subject: