Could not load type IDataServiceUpdateProvider when using REST with SharePoint 2010

I wanted to use the new REST services in SharePoint 2010. But when I navigated to the ListData.svc service. I got the following error:

First, I checked if there was a System.Data.Services entry in the GAC (Global Assembly Cache). There was one with version 3.5.30729.1. So, it was not a missing file.

Searching the web on the error Could not load type 'System.­Data.­Services.­Providers.­IDataServiceUpdateProvider' from assembly 'System.­Data.­Services, Version=3.5.0.0, Culture=­neutral, PublicKeyToken=­b77a5c561934e089' does not provide many hints to what is causing this error.
Most sites suggest to install ADO.NET Data Services v1.5 CTP2, but I already had.

I finally found the page REST and SharePoint 2010 Quick Start Guide by Scott Currier. He suggests to install the ADO.NET Data Services Update for .NET 3.5 SP1. As it turns out, this is the final release of the ADO.NET Services v1.5!

The update comes in two flavors.

For Windows 7 AND Windows Server 2008 R2

Download the ADO.NET Data Services Update for .NET Framework 3.5 SP1 for Windows 7 and Windows Server 2008 R2.

After installing the version of the System.Data.Services.dll file is 3.5.30729.5004.

For Windows 2000, Windows XP, Windows Vista, Windows Server 2003 AND Windows Server 2008

Download the ADO.NET Data Services Update for .NET Framework 3.5 SP1 for Windows 2000, Windows Server 2003, Windows XP, Windows Vista and Windows Server 2008.

After installing the version of the System.Data.Services.dll file is 3.5.30729.4466.

Testing

After I installed the update, I browsed to the ListData.svc service.

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