Unable to update and delete a project using PSI in Project Server 2013

The error I am getting is :

ProjectServerError(s) LastError=GeneralQueueInvalidJobUID Instructions: Pass this into PSClientError constructor to access all error information

public static void UpdateProject()

        {
            project.Url = PROJECT_SERVICE_PATH;
            project.Credentials = System.Net.CredentialCache.DefaultCredentials;
            project.CookieContainer = cookies;
            project.UnsafeAuthenticatedConnectionSharing = true;
            string projectName = "";
            string projectStartDate = null;
            string projectFinishDate = null;
            string projectOwnerId = null;

            Guid projectGuid = new Guid("15bbd49e-14b2-4669-a8b6-02a97a917a80");
            SvcProject.ProjectDataSet projectDS = project.ReadProject(projectGuid, SvcProject.DataStoreEnum.PublishedStore);

            project.CheckOutProject(projectGuid, sessionUID, sessionDescription);
            //project.ProjectTeamDataSet.ProjectTeamRow newResource = projectDS.ProjectTeam.NewProjectTeamRow(); 
            projectDS.Project[0].BeginEdit();
            Console.WriteLine(projectDS.Project[0].ENTERPRISE_PROJECT_TYPE_NAME.ToString());
            projectDS.Project[0].PROJ_INFO_START_DATE = DateTime.Today;
            projectDS.Project[0].PROJ_INFO_FINISH_DATE = DateTime.Today;
            projectDS.Project[0].EndEdit();
            Guid jobGuid = new Guid();

            project.QueueUpdateProjectAsync(jobGuid, sessionUID,projectDS, true);
            jobGuid = new Guid();
            Console.WriteLine("Changes done");
            project.QueueCheckInProject(jobGuid, projectGuid, true, sessionUID, sessionDescription);

            if (projectDS.Project.Count > 0)
            {
                projectName = projectDS.Project[0].PROJ_NAME.ToString();
                projectStartDate = projectDS.Project[0].PROJ_INFO_START_DATE.ToString();
                projectFinishDate = projectDS.Project[0].PROJ_INFO_FINISH_DATE.ToString();
                projectOwnerId = projectDS.Project[0].ProjectOwnerID.ToString();
            }
            Console.WriteLine(projectName);
            Console.WriteLine(projectStartDate);
            Console.WriteLine(projectFinishDate);
            Console.WriteLine(projectOwnerId);
        }

        public static void DeleteProject()
        {
            project.Url = PROJECT_SERVICE_PATH;
            project.Credentials = System.Net.CredentialCache.DefaultCredentials;
            project.CookieContainer = cookies;
            project.UnsafeAuthenticatedConnectionSharing = true;

            WebSvcQueue.QueueSystem q = new WebSvcQueue.QueueSystem();
            q.Url = QUEUESYSTEM_SERVICE_PATH;
            q.UseDefaultCredentials = true;

            string projectName="";
            string projectStartDate = null;
            string projectFinishDate = null;
            string projectOwnerId = null;

            Guid projectGuid = new Guid("758163fe-fb82-41ec-8a43-e57bc7db75e7");
            Guid[] projectGuids = {new Guid("758163fe-fb82-41ec-8a43-e57bc7db75e7")};
            Guid jobGuid = new Guid();
            SvcProject.ProjectDataSet projectDS = project.ReadProject(projectGuid,SvcProject.DataStoreEnum.WorkingStore);
            if (projectDS.Project.Count > 0)
            {
                projectName = projectDS.Project[0].PROJ_NAME.ToString();
                projectStartDate = projectDS.Project[0].PROJ_INFO_START_DATE.ToString();
                projectFinishDate = projectDS.Project[0].PROJ_INFO_FINISH_DATE.ToString();
            }
            else
            {
                Console.WriteLine("No projects returned");
            }
            //try
            //{
                project.QueueDeleteProjects(jobGuid,false, projectGuids, false);
                WaitForQueue(q, jobGuid);
            //}
            //catch (Exception e)
            //{
            //    Console.WriteLine(e.Message.ToString());
            //}
            Console.WriteLine("Project Deleted Successfully");
        }