Here is one cause of the error below. In this case, a fellow developer GAC’ed the .DLL in the Deployment/bin instead of the Development/bin. There was a .DLL in the Deployment/bin, but it was much older, and didn’t have the specific orchestration being called for.

Failed while creating a Your.ProjectName.YourOrchestrationName service.

Exception type: ServiceCreationException
The following is a stack trace that identifies the location where the exception occured

at Microsoft.BizTalk.XLANGs.BTXEngine.BTXSession._serviceCreator(Guid& instanceId, Object objCurrMsg)
at Microsoft.XLANGs.Core.ResourceContainer._allocateResource(Guid& key, UInt32 hashKey, ResourceCreator resCreator, Object creationContext)
at Microsoft.XLANGs.Core.ResourceContainer.Dispense(Guid& key, ResourceCreator resCreator, Object creationContext)
at Microsoft.BizTalk.XLANGs.BTXEngine.BTXSession._dispenseService(Guid& instanceId, IBTMessage currMsg)
at Microsoft.BizTalk.XLANGs.BTXEngine.BTXSession._tryReceiveOneMessage(Boolean& loggedError, Guid& instanceId, IBTMessage currMsg)
at Microsoft.BizTalk.XLANGs.BTXEngine.BTXSession._receiveOneMessage(Guid& instanceId, Guid& serviceId, IBTMessage currentMsg)
at Microsoft.BizTalk.XLANGs.BTXEngine.BTXSession.ReceiveMessages(IBTMessage[] messages, Int32 firstIdx, Int32 count)
at Microsoft.BizTalk.XLANGs.BTXEngine.AppDomains.AppDomainRoot.Microsoft.XLANGs.BizTalk.ProcessInterface.IAppDomainStub.ReceiveMessages(Object objMsg)
at Microsoft.XLANGs.BizTalk.CrossProcess.AppDomainStubProxy.Microsoft.XLANGs.BizTalk.ProcessInterface.IAppDomainStub.ReceiveMessages(Object msgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink._PrivateProcessMessage(IntPtr md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.PrivateProcessMessage(RuntimeMethodHandle md, Object[] args, Object server, Int32 methodPtr, Boolean fExecuteInContext, Object[]& outArgs)
at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg, Int32 methodPtr, Boolean fExecuteInContext)
at System.Runtime.Remoting.Messaging.StackBuilderSink.SyncProcessMessage(IMessage msg)