Error Installing Umbraco 7.0.0: Validation of viewstate MAC failed.

I am installing Umbraco 7.0.0 and got to the step where I enter my "Database Configuration" and press "Install" and I got the error below.

I already tried changing this line in web.config:

to this:

and that did not help.

Please et me know if you can help fix this problem, here is the error:

Server Error in '/' Application.

Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

Source Error:

 The source code that generated this unhandled exception can only be shown when compiled in debug mode. To enable this, please follow one of the below steps, then request the URL:

1. Add a "Debug=true" directive at the top of the file that generated the error. Example:

   <%@ Page Language="C#" Debug="true" %>

or:

2) Add the following section to the configuration file of your application:

<configuration>
    <system.web>
        <compilation debug="true"/>
    </system.web>
</configuration>

 Note that this second technique will cause all files within a given application to be compiled in debug mode. The first technique will cause only that particular file to be compiled in debug mode.

Important: Running applications in debug mode does incur a memory/performance overhead. You should make sure that an application has debugging disabled before deploying into production scenario.

Stack Trace:


[ViewStateException: Invalid viewstate. 
    Client IP: 174.24.204.79
    Port: 34953
    Referer: http://sketchmotion.com/install/?installStep=database
    Path: /install/Default.aspx
    User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; Trident/7.0; Touch; rv:11.0) like Gecko
    ViewState: dnz87BjATxwkoWvNSNONEufeZ/2cZM7P3aM3itKb+dpvUO5pjrV9MnSo8+hmhydvL9TOnudeBFoTSE2yL1xzN1v/sMYmmO34gFMfP61Wt5ADonvR5IRDG30C5gPc5Im6DdioiwEpwQEbBamxSzFAmn3u8n3MDM7SAY2JD0eNlQ72V5W1egmVjNYApGVfAK6e]

[HttpException (0x80004005): Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.]
   System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) +198
   System.Web.UI.ObjectStateFormatter.Deserialize(String inputString, Purpose purpose) +432
   System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter2.Deserialize(String serializedState, Purpose purpose) +8
   System.Web.UI.Util.DeserializeWithAssert(IStateFormatter2 formatter, String serializedState, Purpose purpose) +40
   System.Web.UI.HiddenFieldPageStatePersister.Load() +248
   System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +88
   System.Web.UI.Page.LoadAllState() +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6704
   System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +245
   System.Web.UI.Page.ProcessRequest() +72
   System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +21
   System.Web.UI.Page.ProcessRequest(HttpContext context) +58
   ASP.install_default_aspx.ProcessRequest(HttpContext context) +4
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +341
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +69

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.18056