I've seen a number of Tweets with regards to not being able to install Visual Studio 2010 on OS with Bit Locker enabled. This issue was discussed in the Visual Studio 2010 Readme: http://bit.ly/aVMRde section: "2.1.9 Visual Studio 2010 fails to install on a BitLocker-enabled hard disk when Protection is On"
The known issue is when the install is installing to a custom path and then reboots during setup, if the drive is not unlocked when the OS logs in then the auto relaunch will fail. It is not a big deal, all you need to do is to restart your setup, which will ask you for your setup settings again. This might repeat once, but then you will be fine.
Alternatively, avoid this issue entirely by preinstalling the .NET Framework 4 and Windows Installer 4.5 by following the Avoiding Restart during Setup steps.