First of all, you shouldn't be using 1.0.8 of SL, it is super old. The latest versions (eg, 1.6.11) are universal binaries intended to work on both intel and power PC, from OS X 10.4 onward.
Quick usage of JACK:
1. Start up Jack Pilot application, go to Preferences and select your audio interface. Then start JACK.
2. Start up the SooperLooper application
3. In JackPilot, press the Routing button, in the window that pops up, click on the 'system' item in the left column, then *double-click* the 'sooperlooper' item in the *right* column. That connects your hardware inputs to SL's inputs. Then single-click the 'sooperlooper' item in the left column, and double-click the 'system' item in the right column. This connects SL's main output to your hardware outputs.
You should now be able to see the meters in SL move with your input, and you should be able to hear looped output. If you want to monitor your live input, turn up the 'main in mon' control at the top of SL.
You can save your JackPilot setup, which makes step 3 as easy as Load Studio Setup from JackPilot's File menu.