WiX/Burn install .NET 4 framework pre-requisite failing to reboot

I have created a custom UX that needs .NET 4 installed to run. I have followed the instructions on installing .NET 4 as a pre-requisite from Burn, and this works perfectly when a reboot after .NET is not required. However, if a reboot is required I click the reboot now button, but I get the following error:

The log file contains the following:

[09BC:0638][2012-03-13T10:17:33]: Burn v3.6.2221.0, path: C:\Users\test\Desktop\Demo Setup.exe, cmdline: ''
[09BC:0638][2012-03-13T10:17:33]: Setting string variable 'WixBundleName' to value 'Demo.Installer.Setup'
[09BC:0638][2012-03-13T10:17:34]: Setting string variable 'WixBundleLog' to value 'C:\Users\test\AppData\Local\Temp\Demo.Installer.Setup_20120313101734.log'
[09BC:0638][2012-03-13T10:17:34]: Setting string variable 'WixBundleOriginalSource' to value 'C:\Users\test\Desktop\Demo Setup.exe'
[09BC:0638][2012-03-13T10:17:34]: Loading prerequisite bootstrapper application because managed host could not be loaded, error: 0x80070490.
[09BC:0638][2012-03-13T10:17:34]: Detect 2 packages
[09BC:0638][2012-03-13T10:17:34]: Registry key not found. Key = 'SOFTWARE\Microsoft\Net Framework Setup\NDP\v4\Full'
[09BC:0638][2012-03-13T10:17:34]: Registry key not found. Key = 'SOFTWARE\Microsoft\Net Framework Setup\NDP\v4\Full'
[09BC:0638][2012-03-13T10:17:34]: Condition 'Netfx4FullVersion AND (NOT VersionNT64 OR Netfx4x64FullVersion)' evaluates to false.
[09BC:0638][2012-03-13T10:17:34]: Detected package: Netfx4Full, state: Absent, cached: No
[09BC:0638][2012-03-13T10:17:34]: Detect 1 msi features for package: Demo
[09BC:0638][2012-03-13T10:17:34]: Detected package: Demo, feature: ProductFeature, state: Absent
[09BC:0638][2012-03-13T10:17:34]: Detected package: Demo, state: Absent, cached: No
[09BC:0638][2012-03-13T10:17:34]: Detect complete, result: 0x0
[09BC:0638][2012-03-13T10:17:36]: Plan 2 packages, action: Install
[09BC:0638][2012-03-13T10:17:36]: Setting string variable 'WixBundleLog_Netfx4Full' to value 'C:\Users\test\AppData\Local\Temp\Demo.Installer.Setup_20120313101734_0_Netfx4Full.log'
[09BC:0638][2012-03-13T10:17:36]: Planned package: Netfx4Full, state: Absent, default requested: Present, ux requested: Present, execute: Install, rollback: None, cache: Yes, uncache: Yes, dependency: Register
[09BC:0638][2012-03-13T10:17:36]: Planned package: Demo, state: Absent, default requested: Present, ux requested: None, execute: None, rollback: None, cache: No, uncache: No, dependency: Unregister
[09BC:0638][2012-03-13T10:17:36]: Plan complete, result: 0x0
[09BC:0638][2012-03-13T10:17:36]: Apply begin
[056C:0580][2012-03-13T10:17:39]: Caching executable from: 'C:\Users\test\AppData\Local\Temp\{1847dfac-b6bd-4299-917c-094002d7ee0f}\.be\Demo Setup.exe' to: 'C:\ProgramData\Package Cache\{1847dfac-b6bd-4299-917c-094002d7ee0f}\Demo Setup.exe'
[056C:0580][2012-03-13T10:17:39]: Registering bundle dependency key: {1847dfac-b6bd-4299-917c-094002d7ee0f}, version 1.0.0.0
[056C:0BD4][2012-03-13T10:17:40]: Moving payload from working path 'C:\Users\test\AppData\Local\Temp\{1847dfac-b6bd-4299-917c-094002d7ee0f}\Netfx4Full' to path 'C:\ProgramData\Package Cache\58DA3D74DB353AAD03588CBB5CEA8234166D8B99\Prerequisites\dotNetFx40_Full_x86_x64.exe'
[056C:0580][2012-03-13T10:17:40]: Applying package: Netfx4Full, action: Install, path: C:\ProgramData\Package Cache\58DA3D74DB353AAD03588CBB5CEA8234166D8B99\Prerequisites\dotNetFx40_Full_x86_x64.exe, arguments: '"C:\ProgramData\Package Cache\58DA3D74DB353AAD03588CBB5CEA8234166D8B99\Prerequisites\dotNetFx40_Full_x86_x64.exe" /passive /promptrestart'
[056C:0BC4][2012-03-13T10:20:08]: Received system request to shut down the process: critical: No, elevated: Yes, allowed: No
[056C:0580][2012-03-13T10:20:08]: Error 0x80070004: Process returned error: 0x40010004
[056C:0580][2012-03-13T10:20:08]: Error 0x80070004: Failed to execute EXE package.
[09BC:0638][2012-03-13T10:20:08]: Error 0x80070004: Failed to configure per-machine EXE package.
[09BC:0638][2012-03-13T10:20:08]: Error 0x80070004: Failed to execute EXE package.
[09BC:0638][2012-03-13T10:20:08]: Error 0x80070004: Failed to execute apply.
[09BC:0638][2012-03-13T10:20:08]: Apply complete, result: 0x80070004 restart: No

Why is this happening?

That was a bug in an old version of the WiX toolset. Please upgrade to RTM version of WiX v3.6 or later.