Ok, I got themes to work for me now. I dont know if it makes a difference but the first time I typed the command, I typed it like chmod -R 777 /data/ with the "/" at the end as was suggested in the second post. LaserChicken posted a comment a while back and typed it chmod -R 777 /data without the "/" at the end. I dont know if thats what made a difference or maybe I really did just type something wrong the first time. But I successfully installed a theme now so thats working for me.
Galaxy Nexus / HP TouchPad (Both on Jelly Bean)
Palm Pre Plus
Everything before that doesn't matter.