iPad2 locks-up when upgrading to IOS 5.0.1?

Two of my co-workers have experiences problems upgrading to IOS 5.0.1. They both skipped IOS 5.0. One was upgrading an iPad the other an iPad2. Both are experiencing problems after IOS 5.0.1 has been downloaded and during the back-up operation. While backing up the iPads both became un-responsive and just lock-up. Both are using PC's with the latest version of iTunes 10.5. One was upgrading from IOS 4.2 to 5.0.1. The other was upgrading from IOS 4.3.5 to 5.0.1. Anyone experiencing this?