Curious how you installed it, I did a while back with the SVN from secmaniac.com and it worked flawlessly on my pandora.
Giving it another try now to see if i get the same issue as you.
EDIT: This guy had the same error
http://www.backtrack-linux.org/forums/backtrack-bugs/37042-social-engineering-toolkit-v1-2-error.html fix was svn update
Something came up, will have to try this out later on.