Can't create new PowerPoint file from SharePoint Doclib with check-out enforced / deadlocking!

In the WIndows Eventlog of OOS, we see the rest of the error trace. The WS failing doing it's work. But why? I can open PowerPoint from OOS directly, but somth with the SP integration sucks.

WebHost failed to process a request.
 Sender Information: System.ServiceModel.ServiceHostingEnvironment+HostingManager/51166205
 Exception: System.ServiceModel.ServiceActivationException: The service '/p/ppt/view.svc' cannot be activated due to an exception during compilation.  The exception message is: Could not find a base address that matches scheme http for the endpoint with binding CustomBinding. Registered base address schemes are [].. ---> System.InvalidOperationException: Could not find a base address that matches scheme http for the endpoint with binding CustomBinding. Registered base address schemes are [].
   at System.ServiceModel.ServiceHostBase.MakeAbsoluteUri(Uri relativeOrAbsoluteUri, Binding binding, UriSchemeKeyedCollection baseAddresses)
   at System.ServiceModel.Description.ConfigLoader.LoadServiceDescription(ServiceHostBase host, ServiceDescription description, ServiceElement serviceElement, Action`1 addBaseAddress, Boolean skipHost)
   at System.ServiceModel.ServiceHostBase.LoadConfigurationSectionInternal(ConfigLoader configLoader, ServiceDescription description, ServiceElement serviceSection)
   at System.ServiceModel.ServiceHostBase.ApplyConfiguration()
   at System.ServiceModel.ServiceHostBase.InitializeDescription(UriSchemeKeyedCollection baseAddresses)
   at System.ServiceModel.ServiceHost..ctor(Type serviceType, Uri[] baseAddresses)
   at Microsoft.Office.Server.Powerpoint.Web.Services.MultipleBaseAddressServiceHostFactory.CreateServiceHost(Type serviceType, Uri[] allBoundBaseAddresses)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.CreateService(String normalizedVirtualPath, EventTraceActivity eventTraceActivity)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.ActivateService(ServiceActivationInfo serviceActivationInfo, EventTraceActivity eventTraceActivity)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath, EventTraceActivity eventTraceActivity)
   --- End of inner exception stack trace ---
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath, EventTraceActivity eventTraceActivity)
   at System.ServiceModel.ServiceHostingEnvironment.EnsureServiceAvailableFast(String relativeVirtualPath, EventTraceActivity eventTraceActivity)
 Process Name: w3wp
 Process ID: 8224