System.Runtime.InteropServices.COMException when installing Github for Windows

I'm trying to install GitHub for Windows and I get the following error message:

PLATFORM VERSION INFO
    Windows             : 6.0.6002.131072 (Win32NT)
    Common Language Runtime     : 4.0.30319.18052
    System.Deployment.dll       : 4.0.30319.17929 built by: FX45RTMREL
    clr.dll             : 4.0.30319.18052 built by: FX45RTMGDR
    dfdll.dll           : 4.0.30319.17929 built by: FX45RTMREL
    dfshim.dll          : 4.0.41209.0 (Main.041209-0000)

SOURCES
    Deployment url          : http://github-windows.s3.amazonaws.com/GitHub.application

ERROR SUMMARY
    Below is a summary of the errors, details of these errors are listed later in the log.
    * Activation of http://github-windows.s3.amazonaws.com/GitHub.application resulted in exception. Following failure messages were detected:
        + The referenced assembly is not installed on your system. (Exception from HRESULT: 0x800736B3)

COMPONENT STORE TRANSACTION FAILURE SUMMARY
    No transaction error was detected.

WARNINGS
    There were no warnings during this operation.

OPERATION PROGRESS STATUS
    * [04/12/2013 08:29:27] : Activation of http://github-windows.s3.amazonaws.com/GitHub.application has started.

ERROR DETAILS
    Following errors were detected during this operation.
    * [04/12/2013 08:29:27] System.Runtime.InteropServices.COMException
        - The referenced assembly is not installed on your system. (Exception from HRESULT: 0x800736B3)
        - Source: System.Deployment
        - Stack trace:
            at System.Deployment.Internal.Isolation.IStore.GetAssemblyInformation(UInt32 Flags, IDefinitionIdentity DefinitionIdentity, Guid& riid)
            at System.Deployment.Internal.Isolation.Store.GetAssemblyManifest(UInt32 Flags, IDefinitionIdentity DefinitionIdentity)
            at System.Deployment.Application.ComponentStore.GetAssemblyManifest(DefinitionIdentity asmId)
            at System.Deployment.Application.ComponentStore.GetSubscriptionStateInternal(DefinitionIdentity subId)
            at System.Deployment.Application.SubscriptionStore.GetSubscriptionStateInternal(SubscriptionState subState)
            at System.Deployment.Application.SubscriptionStore.CheckAndReferenceApplication(SubscriptionState subState, DefinitionAppId appId, Int64 transactionId)
            at System.Deployment.Application.DownloadManager.DownloadDeploymentManifestDirectBypass(SubscriptionStore subStore, Uri& sourceUri, TempFile& tempFile, SubscriptionState& subState, IDownloadNotification notification, DownloadOptions options, ServerInformation& serverInformation)
            at System.Deployment.Application.DownloadManager.DownloadDeploymentManifestBypass(SubscriptionStore subStore, Uri& sourceUri, TempFile& tempFile, SubscriptionState& subState, IDownloadNotification notification, DownloadOptions options)
            at System.Deployment.Application.ApplicationActivator.PerformDeploymentActivation(Uri activationUri, Boolean isShortcut, String textualSubId, String deploymentProviderUrlFromExtension, BrowserSettings browserSettings, String& errorPageUrl)
            at System.Deployment.Application.ApplicationActivator.ActivateDeploymentWorker(Object state)

COMPONENT STORE TRANSACTION DETAILS
    No transaction information is available.

Does anyone understand what is causing this?

Here are two solutions for you to try, the second manual delete worked for me. (Also make sure you runt he installer with admin privileges.

Its likely to be a problem with the ClickOnce Application Cache. Could you try the following in order to clear the cache

1. Hold down the Windows key and type R.
2. Type in rundll32 %SystemRoot%\system32\dfshim.dll CleanOnlineAppCache in the run dialog and hit Enter.

Then try installing the application.

If that doesn't work, there's a more manual approach to ensuring the cache is cleared - you can delete the ClickOnce Application folder.

• On Windows Vista or higher, this will be the %LocalAppData%\Apps\2.0 directory.
• On Windows XP this will be the %USERPROFILE%\Local Settings\Apps\2.0 directory.

Note that this path may be in a different language if you're using a non-English version of Windows.