Visual-studio – Error starting Visual Studio 2012

I'm getting an error message every time I start Visual Studio. Since I'm also seeing some unexplained behavior in my project, I'd like to resolve this issue.

Error Message

An exception has been encountered. This may be caused by an extension.

You can get more information by examining the file 'C:\Users\Jonathan\AppData\Roaming\Microsoft\VisualStudio\11.0\ActivityLog.xml'.

When I look at the log file, I find two exceptions:

Error 1

Exception Type       : System.Windows.Markup.XamlParseException
Exception Message    : Provide value on 'System.Windows.StaticResourceExtension' threw an exception.
Exception Stack Trace:
    at System.Windows.Markup.WpfXamlLoader.Load(XamlReader xamlReader, IXamlObjectWriterFactory writerFactory, Boolean skipJournaledProperties, Object rootObject, XamlObjectWriterSettings settings, Uri baseUri)
    at System.Windows.Markup.WpfXamlLoader.LoadBaml(XamlReader xamlReader, Boolean skipJournaledProperties, Object rootObject, XamlAccessLevel accessLevel, Uri baseUri)
    at System.Windows.Markup.XamlReader.LoadBaml(Stream stream, ParserContext parserContext, Object parent, Boolean closeStream)
    at System.Windows.Application.LoadComponent(Object component, Uri resourceLocator)
    at SquaredInfinity.VSCommands.UI.Views.DefaultAlertView.InitializeComponent()
    at SquaredInfinity.VSCommands.Foundation.Services.VSCUIService.GetDefaultAlertViewModel(String alertMessage, String alertDialogTitle)
    at SquaredInfinity.Foundation.Presentation.Services.UIService.GetDefaultAlertViewModel(String alertMessage)
    at SquaredInfinity.Foundation.Presentation.Services.UIService.ShowAlert(String message)
    at SquaredInfinity.VSCommands.VSCommandsPackage.Initialize()
Exception Data   : [EmptyOrNull]
Inner Exception:
Exception Type       : System.Exception
Exception Message    : Cannot find resource named 'VSC.Button'. Resource names are case sensitive.
Exception Stack Trace:    at System.Windows.StaticResourceExtension.ProvideValueInternal(IServiceProvider serviceProvider, Boolean allowDeferredReference)
                      at System.Windows.StaticResourceExtension.ProvideValue(IServiceProvider serviceProvider)
                      at MS.Internal.Xaml.Runtime.ClrObjectRuntime.CallProvideValue(MarkupExtension me, IServiceProvider serviceProvider)
Exception Data   : [EmptyOrNull]

Error 2

System.ComponentModel.Composition.CompositionException: The composition produced a single composition error. The root cause is provided below. Review the CompositionException.Errors property for more detailed information.

1) The current type,    SquaredInfinity.Foundation.Configuration.Services.IConfigurationService, is an interface and cannot be constructed. Are you missing a type mapping?
Resulting in: Resolution of the dependency failed, type = "SquaredInfinity.Foundation.Configuration.Services.IConfigurationService", name = "(none)".
Exception occurred while: while resolving.
Exception is: InvalidOperationException - The current type, SquaredInfinity.Foundation.Configuration.Services.IConfigurationService, is an interface and cannot be constructed. Are you missing a type mapping?
-----------------------------------------------
At the time of the exception, the container was:
  Resolving SquaredInfinity.Foundation.Configuration.Services.IConfigurationService,(none)

Resulting in: An exception occurred while trying to create an instance of type '#Btb.#Rtb'.

Resulting in: Cannot activate part '#Btb.#Rtb'.
Element: #Btb.#Rtb -->  #Btb.#Rtb

Resulting in: Cannot get export '#Btb.#Rtb (ContractName="Microsoft.VisualStudio.Text.Classification.IClassifierProvider")' from part '#Btb.#Rtb'.
Element: #Btb.#Rtb (ContractName="Microsoft.VisualStudio.Text.Classification.IClassifierProvider") -->  #Btb.#Rtb

   at System.ComponentModel.Composition.Hosting.CompositionServices.GetExportedValueFromComposedPart(ImportEngine engine, ComposablePart part, ExportDefinition definition)
   at System.ComponentModel.Composition.Hosting.CatalogExportProvider.GetExportedValue(CatalogPart part, ExportDefinition export, Boolean isSharedPart)
   at System.ComponentModel.Composition.Hosting.CatalogExportProvider.CatalogExport.GetExportedValueCore()
   at System.ComponentModel.Composition.Primitives.Export.get_Value()
   at System.ComponentModel.Composition.ExportServices.GetCastedExportedValue[T](Export export)
   at System.ComponentModel.Composition.ExportServices.<>c__DisplayClass4`2.<CreateStronglyTypedLazyOfTM>b__1()
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.LazyInitValue()
   at System.Lazy`1.get_Value()
   at Microsoft.VisualStudio.Text.Utilities.GuardedOperations.InvokeMatchingFactories[TExtensionInstance,TExtensionFactory,TMetadataView](IEnumerable`1 lazyFactories, Func`2 getter, IContentType dataContentType, Object errorSource)

How do I interpret this so that I can figure out the error?