The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)

All my xaml's in WPF are giving me the following error:

System.IO.FileLoadException
The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)
at System.Reflection.AssemblyName.nInit(RuntimeAssembly& assembly, Boolean forIntrospection, Boolean raiseResolveEvent)
at System.Reflection.AssemblyName..ctor(String assemblyName)
at MS.Internal.Design.Metadata.ReflectionProjectNode.FindAssembly(String assembly)
at MS.Internal.Design.Metadata.ReflectionProjectNode.ParseClrNamespaceUri(Identifier namespaceId, Identifier name, String clrNamespaceUri, IParseContext context, Node offendingNode)
at MS.Internal.Design.Metadata.ReflectionProjectNode.EnsureExists(Identifier namespaceUri, Identifier name, IParseContext context, Node offendingNode)
at MS.Internal.Design.Markup.XmlElement.BuildScope(PrefixScope parentScope, IParseContext context)
at MS.Internal.Design.Markup.XmlElement.ConvertToXaml(XamlElement parent, PrefixScope parentScope, IParseContext context, IMarkupSourceProvider provider, Boolean visitCodeModel)
at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.FullParse(Boolean convertToXamlWithErrors)
at MS.Internal.Design.DocumentModel.DocumentTrees.Markup.XamlSourceDocument.get_RootItem()
at Microsoft.Windows.Design.DocumentModel.Trees.ModifiableDocumentTree.get_ModifiableRootItem()
at Microsoft.Windows.Design.DocumentModel.MarkupDocumentManagerBase.get_LoadState()
at MS.Internal.Host.PersistenceSubsystem.Load()
at MS.Internal.Host.Designer.Load()
at MS.Internal.Designer.VSDesigner.Load()
at MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedView.Load()
at MS.Internal.Designer.VSIsolatedDesigner.VSIsolatedDesignerFactory.Load(IsolatedView view)
at MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory factory, IsolatedView view)
at MS.Internal.Host.Isolation.IsolatedDesigner.BootstrapProxy.LoadDesigner(IsolatedDesignerFactory factory, IsolatedView view)
at MS.Internal.Host.Isolation.IsolatedDesigner.Load()
at MS.Internal.Designer.DesignerPane.LoadDesignerView(Boolean isReload)

I'm using Visual Studio 2010 for this. If I use VS 2012, the exceptions are gone and everything is working fine. I've also tried to go under properties -> debug -> and disable 'Enable the Visual Studio hosting process'. I don't have any special characters in my assembly name. It's just called SeatingPlans Anything I'm missing? Don't really get it why VS2012 shows my xaml, but VS2010 doesn't.