Did you install the updated mobilesubstrate too? WB needs the updated one to work...
Yes, I did both. Worked fine for me.
Thanks for the help everyone! Winterboard installed fine, but I don't see MobileSubstrate anywhere in my Cydia packages. Isn't it supposed to appear there as well?
Doesn't show up for me either, not in apps folder or Cydia. Must run in the background.
According to the command window when I unpacked it, it worked.