I restore the registry on a lot of machines and have never had that error.
What is odd is that error has nothing to do with the registry but instead has to do with the file stored at
C:\Windows\System32\Tasks\Microsoft\Windows\WS
And the file is License Validation. That error is saying that it isnt able to read that file properly.
Edit the file with notepad and you can see the xml text in it. You can compare what you have in it from the one I have on my Windows 8.1 system and see if you notice anything different. Post a copy of the file for me so i can look as well.
<?xml version="1.0" encoding="UTF-16"?>
<Task version="1.4" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
<RegistrationInfo>
<Source>$(@%SystemRoot%\system32\wsservice.dll,-122)</Source>
<Date>2010-10-27T17:18:44.0816608</Date>
<Author>$(@%SystemRoot%\system32\wsservice.dll,-120)</Author>
<Description>$(@%SystemRoot%\system32\wsservice.dll,-123)</Description>
<URI>\Microsoft\Windows\WS\License Validation</URI>
<SecurityDescriptor>D:P(A;;FA;;;SY)(A;;FA;;;BA)(A;;GRGX;;;SU)(A;;FA;;;S-1-5-80-1227353651-1023108616-160957920-2792958081-1972711695)(A;;FR;;;S-1-5-87-1452649159-2109950929-2856838567-3638795029-1283063528)</SecurityDescriptor>
</RegistrationInfo>
<Triggers>
<TimeTrigger>
<Repetition>
<Interval>PT6H</Interval>
<StopAtDurationEnd>false</StopAtDurationEnd>
</Repetition>
<StartBoundary>2014-02-20T16:09:10Z</StartBoundary>
<Enabled>true</Enabled>
</TimeTrigger>
</Triggers>
<Principals>
<Principal id="LocalService">
<UserId>S-1-5-19</UserId>
<RunLevel>LeastPrivilege</RunLevel>
</Principal>
</Principals>
<Settings>
<MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
<DisallowStartIfOnBatteries>false</DisallowStartIfOnBatteries>
<StopIfGoingOnBatteries>false</StopIfGoingOnBatteries>
<AllowHardTerminate>false</AllowHardTerminate>
<StartWhenAvailable>true</StartWhenAvailable>
<RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable>
<IdleSettings>
<StopOnIdleEnd>true</StopOnIdleEnd>
<RestartOnIdle>false</RestartOnIdle>
</IdleSettings>
<AllowStartOnDemand>true</AllowStartOnDemand>
<Enabled>true</Enabled>
<Hidden>true</Hidden>
<RunOnlyIfIdle>false</RunOnlyIfIdle>
<DisallowStartOnRemoteAppSession>false</DisallowStartOnRemoteAppSession>
<UseUnifiedSchedulingEngine>true</UseUnifiedSchedulingEngine>
<MaintenanceSettings>
<Period>P1D</Period>
<Deadline>P2D</Deadline>
<Exclusive>false</Exclusive>
</MaintenanceSettings>
<WakeToRun>false</WakeToRun>
<ExecutionTimeLimit>PT0S</ExecutionTimeLimit>
<Priority>7</Priority>
<RestartOnFailure>
<Interval>P31D</Interval>
<Count>255</Count>
</RestartOnFailure>
</Settings>
<Actions Context="LocalService">
<Exec>
<Command>rundll32.exe</Command>
<Arguments>WSClient.dll,WSpTLR licensing</Arguments>
</Exec>
</Actions>
</Task>
Shane