I get a weird Error after upgrading to the latest and greatest EPiServer 9.0.3.0.

Port must be a parsable integer between 0 and 65535 or wildcard character
Parameter name: authority

Something seams to be wrong with initialization of XForms. Anybody got an idea what might be wrong?

Full stack trace:

[ArgumentException: Port must be a parsable integer between 0 and 65535 or wildcard character
Parameter name: authority]
   EPiServer.Web.UriAuthority..ctor(String authority) +628
   EPiServer.Web.HostDefinition.set_Name(String value) +63
   EPiServer.DataAccess.SiteDefinitionDB.HostDefinitionFromReader(IDataRecord r) +70
   EPiServer.DataAccess.SiteDefinitionDB.b__0() +358
   EPiServer.Data.Providers.<>c__DisplayClass2f`1.b__2e() +59
   EPiServer.Data.Providers.SqlTransientErrorsRetryPolicy.Execute(Func`1 method) +45
   EPiServer.Data.Providers.SqlDatabaseHandler.Execute(Func`1 action) +202
   EPiServer.DataAccess.SiteDefinitionDB.List() +79
   EPiServer.Web.SiteDefinitionRepository.List() +50
   EPiServer.Web.SiteDefinitionResolver.GetByHostName(String hostName, Boolean fallbackToWildcard, HostDefinition& matchedHost) +109
   EPiServer.Web.SiteDefinitionResolver.GetByHostName(String hostName, Boolean fallbackToWildcard) +25
   EPiServer.Web.SiteDefinitionResolver.Get(HttpRequestBase request) +27
   EPiServer.Web.SiteDefinition.b__1(SiteDefinitionResolver s, HttpRequestBase r) +10
   EPiServer.Web.SiteDefinition.GetCurrentInternal(Func`3 resolveSiteDefinition) +271
   EPiServer.Web.SiteDefinition.get_Current() +66
   EPiServer.Initialization.XFormsInitialization.Initialize(InitializationEngine context) +156
   EPiServer.Framework.Initialization.<>c__DisplayClass5.b__4() +19
   EPiServer.Framework.Initialization.ModuleNode.Execute(Action a, String key) +43
   EPiServer.Framework.Initialization.ModuleNode.Initialize(InitializationEngine context) +80
   EPiServer.Framework.Initialization.InitializationEngine.InitializeModules() +173

[InitializationException: Initialize action failed for Initialize on class EPiServer.Initialization.XFormsInitialization, EPiServer, Version=9.0.3.0, Culture=neutral, PublicKeyToken=8fe83dea738b45b7]
   EPiServer.Framework.Initialization.InitializationEngine.InitializeModules() +439
   EPiServer.Framework.Initialization.InitializationEngine.Initialize(HostType hostType) +116
   EPiServer.Framework.Initialization.InitializationModule.Initialize(HostType hostType) +475
   EPiServer.Framework.Initialization.InitializationModule.FrameworkInitialization(HostType hostType) +83
   EPiServer.Global..ctor() +76
   Wiki.Web.EPiServerApplication..ctor() +42
   ASP.global_asax..ctor() in c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\root\ae0bf895\450407ad\App_global.asax.xcgnyrkz.0.cs:0

[TargetInvocationException: Ett undantagsfel har inträffat i målet för en aktivering.]
   System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck) +0
   System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +119
   System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark) +232
   System.Activator.CreateInstance(Type type, Boolean nonPublic) +83
   System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark) +1117
   System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) +124
   System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture) +20
   System.Web.HttpRuntime.CreateNonPublicInstance(Type type, Object[] args) +60
   System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +276
   System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +296

[HttpException (0x80004005): Ett undantagsfel har inträffat i målet för en aktivering.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +9920756
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +101
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +261