A startup bug has been discovered in the latest RC1 release. A new release (RC2) will be out tonight to address this issue. In the meantime, if you look at bug #1485932, titled Linux install problem, you will find a file attached that you can drop into your lib/ directory to fix the problem. Otherwise, please wait for the new release tonight.
This issue only affects first time users of InstallJammer.
The InstallJammer Team