Hi,
The YUI scripts and the jQuery scripts are loaded form the internet using the google CDN (Content Delivery Network). So if your machine is not connected to the internet you may get script errors because it can't load the scripts. Its possible (but not trivial) to download the needed scripts and then host them from within the mojoportal site, but it takes some configuration and understanding of mojoPortal.
That combine javscript was something I experimented with but it did not work well, it should be left as false. The scripts are not combined, they are loaded from the google cdn.
Hope it helps,
Joe