Corelyzer, starting from version 0.6 makes use of the Java Runtime Environment (JRE). The current version of Corelyzer requires Java Runtime Environment above version 1.5.0. Please make sure to install Java 1.5.
For Microsoft Windows users, Corelyzer will bundle a copy of JRE within the downloaded package. You should not have to install JRE separately.
For Mac users, in the current Mac OS X Leopard, Java is bundled with the operating system. In some cases of Mac OS X Tiger installation, Java 1.4 might be still presented in the system. In that case, you will have to modify the default version to version 1.5.