If I remember correctly, to unlock an app/folder, when I had it, all you have to do is press the icon/folder on the springboard - a pop-up would appear to prompt you to put in your password. If that's not happening, well, sorry, but I guess I remembered incorrectly. I had it for a bit, but since I was the only one using my iPad, I took it off. And that was quite a while ago, sorry.
For those of you JB'd on iOS 5: Don't install Locktopus!
Locktopus is not compatible with iOS 5. So, in the interest of your iPad's well-being ... don't use it.
My information is from the Google spreadsheet "Official iOS 5 Cydia Tweak Compatibility List [Publicly Maintained]," which is an Excel file that is updated and maintained by the jail break community as they find stuff that works or doesn't.
</public service announcement>
Sorry, Dr. Gee, for side-tracking your thread for that announcement.
But, I hope what I provided you above helps. Let us know how you get on.
Marilyn