Apple has released a new seed of Mac OS 10.7.2 and a new beta of iCloud for Mac. Mac OS 10.7.2 build 11C35 and iCloud for Mac beta 6 are both required to complete the MobileMe to iCloud transition process.
Per 10.7.2 release notes:
This pre-release version of OS X Lion 10.7.2 is being provided solely for testing iCloud and updates the public release of OS X Lion and any earlier seed of OS X Lion 10.7.2.
If you installed a previous seed of OS X Lion 10.7.2, please run the included reversioner package followed by the OS X Lion 10.7.2 update without restarting your system.
You should restart your system after installing the OS X Lion 10.7.2 Update. (Mac Developer Program membership is required).
iCloud for Mac beta 6:
iCloud Add-on installer for OS X Lion. (Mac Developer Program membership is required).