Error loading project (#1553)

When I try to open a specific existing project, I get the error message mentioned at the bottom. Other projects can be opened. There is a backup file that also cannot be opened.

Please help, that is an important file to me.

Regards

Stefan Menten

System.ArgumentNullException: Der Wert darf nicht NULL sein.

Parametername: key

bei System.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)

bei System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)

bei SoftwareIdeasModeler.Synchro.Synchronization.NotifyingDictionary`2.Add(TKey key, TValue value)

bei SoftwareIdeasModeler.Core.DiagramItems.DecisionTable.DecisionTableRule.FromXElement(DecisionTable owner, XElement xElement)

bei SoftwareIdeasModeler.Core.DiagramItems.DecisionTable.DecisionTable.FromXElement(Project project, XElement xElement)

bei SoftwareIdeasModeler.Core.DiagramItems.DecisionTable.DecisionTableElement.SetDetailsFromXElement(SimXmlReader reader, XElement xElem)

bei SoftwareIdeasModeler.Core.Projecting.Diagram.LoadAbstractItems(SimXmlReader reader, Diagram diagram, XElement root)

bei SoftwareIdeasModeler.Core.Projecting.Diagram.FromXElement(SimXmlReader reader, IDiagramOwner owner, XElement elem)

bei SoftwareIdeasModeler.Core.Projecting.Folder.FromXElement(SimXmlReader reader, Project project, XElement elem)

bei SoftwareIdeasModeler.ProjectXml.SimXmlReader.LoadFolders(XElement root)

bei SoftwareIdeasModeler.ProjectXml.SimXmlReader.Load()

bei SoftwareIdeasModeler.ProjectHelper.LoadProject(String localFileName, Boolean showReadOnlyWarning, Boolean checkFileVersion, Boolean processCustomDiagrams)

bei SoftwareIdeasModeler.ProjectHelper.LoadProject(String filename, String repositoryPath)