Lots of people who tried jailbreaking their iPad 2 or iPhone using the initial command line release experienced errors and problems. Thankfully, Absinthe for PC (think of it as Jailbreak 2.0, if you wish) is already available, a simple application that you can run and which should work. You may want to make a backup and then reset it completely, if you find you still hit problems.
You can download the Absinthe jailbreaking app for PC via this link, or this mirror or this one. Enjoy!