Chronic Dev Team just updated Absinthe to v2.0.4, adds support iPad2,4 - a revised version of the iPad 2. If you failed jailbroken with your iPad 2, you could try new version now.
Now Absinthe 2.0 supports the following devices on 5.1.1:
iPad 1, iPad 2, iPad 3 (iPad2,4 is now supported as of Absinthe 2.0.4)
iPhone 3GS, iPhone 4, iPhone 4S
iPod touch 3rd generation, iPod touch 4th generation