To use Jubler you need at least JDK 1.7. Unfortunately there is no such bundle for Mac OS 10.6. Still, thanks to Wyatt8740, there is a version available for you (also leave him a positive feedback!). Steps to install it:
/Library/Java/JavaVirtualMachines/
It is recommended to leave the preferences as is. Let the newest version be the default instead of the older 6 version.