I'm pretty sure InsaneJournal didn't grab any file they didn't have the right to grab i.e. files that weren't in lj non-free. I remember people importing layouts over there without knowing (or caring) about licensing terms but these were personal initiatives.

To the OP: you're probably getting errors because you're trying to make it a Core2 layout - i.e. newer, better code DW layouts use - instead of a Core1 layout, as Zvi mentioned in the link she gave you.