Getting error while deleting task Id from task engine Administration of MWS

Hi All,
Am getting below error while trying to deletin the task from (Administration–>Business–>Tasks—>Task Engine Adminsitration), am using webmethods 8.0.1

com.webmethods.caf.faces.data.ContentProviderException: ID not found: 1AA90A07-70C4-759D-F322-AF269BC23DB5
at com.webmethods.caf.faces.data.portal.PortalContainerModel.getURI(PortalContainerModel.java:146)
at com.webmethods.caf.faces.data.portal.PortalItemModel.refresh(PortalItemModel.java:230)
at com.webmethods.caf.faces.data.portal.PortalItemModel.getValue(PortalItemModel.java:173)
at com.webmethods.portlet.tasktypesearch.TaskTypeSearchViewPage.canDeleteTaskType(TaskTypeSearchViewPage.java:341)
at com.webmethods.portlet.tasktypesearch.TaskTypeSearchViewPage.getCanDeleteTaskType(TaskTypeSearchViewPage.java:335)
at sun.reflect.GeneratedMethodAccessor3581.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at javax.el.BeanELResolver.getValue(BeanELResolver.java:261)
at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:143)
at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:73)
at com.sun.el.parser.AstValue.getValue(AstValue.java:138)
at com.sun.el.parser.AstNot.getValue(AstNot.java:59)
at com.sun.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:206)
at com.sun.faces.application.ValueBindingValueExpressionAdapter.getValue(ValueBindingValueExpressionAdapter.java:113)
at com.webmethods.caf.faces.application.CAFValueBinding.getValue(CAFValueBinding.java:56)
at com.webmethods.caf.faces.component.util.ComponentUtils.getPropertyOrBindingValue(ComponentUtils.java:172)
at com.webmethods.caf.faces.component.logic.If.getValue(If.java:53)
at com.webmethods.caf.faces.component.logic.If.isRendered(If.java:38)
at com.webmethods.caf.faces.component.table.html.DataTable.processColumnChild(DataTable.java:1446)
at com.webmethods.caf.faces.component.table.html.DataTable.iterate(DataTable.java:1325)
at com.webmethods.caf.faces.component.table.html.DataTable.processUpdates(DataTable.java:947)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1070)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1070)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1070)
at com.webmethods.caf.faces.component.panel.BaseHideablePanel.processUpdates(BaseHideablePanel.java:149)
at javax.faces.component.UIForm.processUpdates(UIForm.java:261)
at com.webmethods.caf.faces.component.command.html.CommandForm.processUpdates(CommandForm.java:64)
at javax.faces.component.UIComponentBase.processUpdates(UIComponentBase.java:1070)
at javax.faces.component.UIViewRoot.processUpdates(UIViewRoot.java:717)
at com.webmethods.caf.faces.component.ViewRoot.processUpdates(ViewRoot.java:108)
at com.webmethods.caf.faces.portlet.PortletLifecycle$UpdateModelValuesPhase.execute(PortletLifecycle.java:661)
at com.webmethods.caf.faces.portlet.PortletLifecycle.phase(PortletLifecycle.java:250)
at com.webmethods.caf.faces.portlet.PortletLifecycle.execute(PortletLifecycle.java:145)
at com.webmethods.caf.faces.portlet.FacesPortlet.processAction(FacesPortlet.java:245)
at com.webmethods.portal.framework.portletcontainer.impl.PortletApplicationHandler.process(PortletApplicationHandler.java:479)
at com.webmethods.portal.framework.portletcontainer.servlet.PortletServlet.service(PortletServlet.java:58)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:726)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispatcher.java:285)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispatcher.java:126)
at com.webmethods.portal.framework.portletcontainer.PortletContainer.dispatch(PortletContainer.java:218)
at com.webmethods.portal.framework.portletcontainer.PortletContainer.process(PortletContainer.java:129)
at com.webmethods.portal.framework.portletcontainer.PortletContainer.processPortletAction(PortletContainer.java:107)
at com.webmethods.portal.framework.portlet.beans.rest.RestfulPCAHandler.handle(RestfulPCAHandler.java:194)
at com.webmethods.portal.framework.dispatch.DispatchManager.handle(DispatchManager.java:442)
at com.webmethods.portal.framework.dispatch.DispatchManager.handleDispatch(DispatchManager.java:372)
at com.webmethods.portal.framework.impl.PortalServlet.service(PortalServlet.java:245)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
at com.webmethods.portal.framework.impl.NTLMFilter.doFilter(NTLMFilter.java:50)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at com.webmethods.caf.faces.servlet.GZIPFilter.doFilter(GZIPFilter.java:42)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:726)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:206)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:842)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:648)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:450)

please let me know how to solve this problem.
regards,
Anil Kumar Ellendula