Thank you very much, meirs!
As for the worlds I tried to import, they can be found and downloaded in this post.
http://www.alice.org/community/showthread.php?t=3205
I tried importing Resident Penguin 1, 3.1, and 3.5. None of them have any speech bubbles or thought bubbles, but all three are somewhat complex. RP1 imported, but the controls didn't work properly. The other two threw an error message halfway through loading.
Please tell me if they import for you so I know if the issue is with my computer.
Thanks again!