Sitecore 8 Experience Editor: A serious error has occurred please contact the administrator

Hi,

In Sitecore version 8.0 rev. 150621 I am experiencing issue when clicking on Experience Editor or Preview button in the Publish tab. The experience editor opens with the "A serious error has occurred please contact the administrator" message and in the log I get the following entries:

 

7292 16:26:44 ERROR Error processing command url:/-/speak/request/v1/expeditor/experienceeditor.breadcrumb.getstructure error:System.InvalidOperationException: Could not retrieve request class for url:/-/speak/request/v1/expeditor/experienceeditor.breadcrumb.getstructure
at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.Process(HttpContext context)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.ProcessRequest(HttpContext context)
6752 16:26:45 ERROR Error processing command url:/-/speak/request/v1/expeditor/optimization.activeitemtest error:System.InvalidOperationException: Could not retrieve request class for url:/-/speak/request/v1/expeditor/optimization.activeitemtest
at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.Process(HttpContext context)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.ProcessRequest(HttpContext context)
4008 16:26:45 ERROR Error processing command url:/-/speak/request/v1/expeditor/experienceeditor.item.notifications error:System.InvalidOperationException: Could not retrieve request class for url:/-/speak/request/v1/expeditor/experienceeditor.item.notifications
at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.Process(HttpContext context)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.ProcessRequest(HttpContext context)
11652 16:26:45 ERROR Error processing command url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get error:System.InvalidOperationException: Could not retrieve request class for url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get
at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.Process(HttpContext context)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.ProcessRequest(HttpContext context)
6752 16:26:45 ERROR Error processing command url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get error:System.InvalidOperationException: Could not retrieve request class for url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get
at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.Process(HttpContext context)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.ProcessRequest(HttpContext context)
4128 16:26:46 ERROR Error processing command url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get error:System.InvalidOperationException: Could not retrieve request class for url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get
at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.Process(HttpContext context)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.ProcessRequest(HttpContext context)
7292 16:26:46 ERROR Error processing command url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get error:System.InvalidOperationException: Could not retrieve request class for url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get
at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.Process(HttpContext context)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.ProcessRequest(HttpContext context)
9844 16:26:46 ERROR Error processing command url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get error:System.InvalidOperationException: Could not retrieve request class for url:/-/speak/request/v1/expeditor/experienceeditor.toggleregistrykey.get
at Sitecore.Diagnostics.Assert.IsNotNull(Object value, String message)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.Process(HttpContext context)
at Sitecore.ExperienceEditor.Speak.Server.RequestHandler.ProcessRequest(HttpContext context)

I already tried the solution suggested here https://community.sitecore.net/developers/f/5/t/3049 but still have this problem. Any ideas?

Thanks