New Post: Error when trying edit/open page

I'm getting an error when trying to edit/open a page that is already opened by another user.

Version 4.1

Here is the log file....

2013-12-23 08:46:05.82 System.InvalidOperationException: Cannot find ICompositionContainer by ID: 'eb210a75-be25-401f-b0d4-b3787bce36fa'
at Composite.C1Console.Workflow.WorkflowFacadeImpl.RunWorkflow(Guid instanceId)
at Composite.C1Console.Workflow.WorkflowFacadeImpl.RunWorkflow(WorkflowInstance workflowInstance)
at Composite.C1Console.Workflow.WorkflowActionExecutor.Execute(String serializedEntityToken, String serializedActionToken, ActionToken actionToken, FlowControllerServicesContainer flowControllerServicesContainer)
at Composite.C1Console.Actions.ActionExecutorFacade.Execute(IActionExecutorSerializedParameters actionExecutor, String serializedEntityToken, String serializedActionToken, ActionToken actionToken, FlowControllerServicesContainer flowControllerServicesContainer)
at Composite.C1Console.Actions.ActionExecutorFacade.Execute(EntityToken entityToken, ActionToken actionToken, FlowControllerServicesContainer flowControllerServicesContainer, TaskManagerEvent taskManagerEvent)
at Composite.Core.WebClient.FlowMediators.ActionExecutionMediator.ExecuteElementAction(ElementHandle elementHandle, ActionHandle actionHandle, String consoleId)
at Composite.Core.WebClient.FlowMediators.TreeServicesFacade.ExecuteElementAction(String providerName, String serializedEntityToken, String piggybag, String serializedActionToken, String consoleId)
at Composite.Services.TreeServices.ExecuteSingleElementAction(ClientElement clientElement, String serializedActionToken, String consoleId) in c:\inetpub\wwwroot\CMS41\Composite\services\Tree\TreeServices.asmx:line 211
TreeService Error
2013-12-23 08:46:05.82 System.InvalidOperationException: Cannot find ICompositionContainer by ID: 'eb210a75-be25-401f-b0d4-b3787bce36fa'
at Composite.Data.PageMetaDataFacade.<GetAllowedMetaDataContainers>d__1c.MoveNext()
at System.Collections.Generic.List1..ctor(IEnumerable1 collection)
at Composite.Core.Linq.IEnumerableExtensions.Evaluate[T](IEnumerable1 enumerable)
at Composite.Plugins.Elements.ElementProviders.PageElementProvider.EditPageWorkflow.editStateCodeActivity_ExecuteCode(Object sender, EventArgs e)
at System.Workflow.ComponentModel.Activity.RaiseEvent(DependencyProperty dependencyEvent, Object sender, EventArgs e)
at System.Workflow.Activities.CodeActivity.Execute(ActivityExecutionContext executionContext)
at System.Workflow.ComponentModel.ActivityExecutor1.Execute(T activity, ActivityExecutionContext executionContext)
at System.Workflow.ComponentModel.ActivityExecutorOperation.Run(IWorkflowCoreRuntime workflowCoreRuntime)
at System.Workflow.Runtime.Scheduler.Run()

I can't get to the bottom of this... any ideas what went wrong here?