Why do I get error 0x80070004 when trying to update to Windows 8.1 from Windows 8?

So, I'm trying to update Windows 8 to Windows 8.1 via the Windows Store, but every time I attempt to, the update downloads properly, but then I get the error:

Windows 8.1
This app wasn't installed - view details

When I click on it, it says:

Something happened and the Windows 8.1 could not be installed. Please try again. Error code: 0x80070004
Try again Cancel Install

What does this mean? A quick Google search yields nothing.

I have tried rebooting, clearing the store cache, and resetting Windows Update. All Windows Updates were installed. I have tried using a different administrator account, and it does not work.

A quick chkdsk scan shows no errors.

A SFC scan now shows no errors.

I found the error log!

http://pastebin.com/BXZEsejm

Why is the registry corrupt?

DISM Results

Checking System Update Readiness.


Summary:
Operation: Detect and Repair 
Operation result: 0x0
Last Successful Step: Entire operation completes.
Total Detected Corruption:  0
Total Repaired Corruption:  0
    CSI Store Metadata refreshed:   True

Total Operation Time: 1405 seconds.

You seem to have problems in Windows 8. There is no point in trying to upgrade to 8.1 without fixing them first and verifying that "sfc /scannow" passes without errors and also that Windows Update is functional and can fully patch your Windows installation.

Some utilities that could help you check for problems are :

• Use the inbox Deployment Image Servicing and Management (DISM) tool to fix corruption errors.
  This creates a log file that could help us if posted.
• Windows Repair (All In One)
• Disable any third-party antivirus or security suite.

If none of them helps, Do a Repair Install of Windows 8 without Losing Anything.

The next step is to verify if your user profile got corrupted. Follow the instructions in the article How to fix corrupt user profile in windows 8 to create a new administrator profile and see if it can do better than your old account.

If nothing helps, my remaining advice is to look up the article How to refresh, reset, or restore your PC. If the problem is recent, try first to restore to a system restore point that dates from before the problem appeared. If that doesn't help, then try a Refresh, with a Reset as the last possible action. If Reset does not work, reformat the disk and reinstall Windows 8 from DVD or USB.

In all cases, ensure before starting that all your data is safely backed up.

Once "sfc /scannow" and Windows Update pass without errors, follow the steps outlined in the article :
Fix: Your Windows 8.1 install couldn’t be completed error.

In a nutshell, the instructions are to open a Command Prompt as administrator, then enter :

net stop wuauserv
net stop bits

Then browse to the C:\Windows\SoftwareDistribution folder and delete all the files and folders inside (restart if in use).

Then enter the following commands :

net start wuauserv
net start bits

Now open the Windows Store and try the upgrading process all over again.

If you still have errors with the Store, some advice :

• Disable all security products
• In Command Prompt (cmd) Run as Administrator, execute WSReset.exe to reset the Store