2356551 - PI Message Monitor does not load, error message "Cannot access object class loader for deployable object..."

You have an AS Java PI/PO 7.5 system that just got upgraded to SP03.

After the upgrade you tried to open the Message Monitor in NetWeaver Administrator, but the monitor is not loaded and the following error message pops up:
com.sap.tc.webdynpro.services.sal.deployment.core.ClassLoaderException: Cannot access object class loader for deployable object sap.com/tc~lm~itsam~co~ui~xi~msg~wd

In the Default trace the following entries can be seen:

Exception while getting navigation parameters for related task.
[EXCEPTION]
com.sap.tc.webdynpro.services.exceptions.WDRuntimeException: ComponentUsage(com.sap.lm.itsam.ui.floorplan.FloorPlan:EmbeddedApplicationInst, createOnDemand=false, no active component): Active component must exist when getting interface controller. (Hint: Have you forgotten to create it with createComponent()? Should the lifecycle control of the component usage be "createOnDemand"?)
at com.sap.tc.webdynpro.progmodel.components.ComponentUsage.ensureActiveComponent(ComponentUsage.java:1195)
Error loading embedded application (componet - com.sap.tc.lm.itsam.co.ui.xi.msg.ximessagedetailed.XIMessageDetailed.
[EXCEPTION]
com.sap.tc.webdynpro.services.sal.deployment.core.ClassLoaderException: Cannot access object class loader for deployable object sap.com/tc~lm~itsam~co~ui~xi~msg~wd.
at com.sap.tc.webdynpro.serverimpl.wdc.deployment.DeployableObject.getClassLoader(DeployableObject.java:105)
at com.sap.tc.webdynpro.serverimpl.core.repository.AbstractServerRepository.getDeployableObjectClassloader(AbstractServerRepository.java:125)
at com.sap.tc.webdynpro.repository.model.Repository.getRepositoryModelInternal(Repository.java:639)
at com.sap.tc.webdynpro.repository.persistence.RepositoryPersistence.createEmptyVmoForParsing(RepositoryPersistence.java:677)
at com.sap.tc.webdynpro.repository.persistence.xml.XMLPersistence.doReadVMO(XMLPersistence.java:96)

Caused by: com.sap.engine.services.servlets_jsp.server.deploy.impl.exceptions.WCEApplicationNotStartedException: Failed explicit start for application [sap.com/tc~lm~itsam~co~ui~xi~msg~wd].
at com.sap.engine.services.servlets_jsp.server.deploy.impl.ApplicationManager.start(ApplicationManager.java:181)
at com.sap.engine.services.servlets_jsp.server.deploy.impl.ApplicationManager.analyseAppStatusMode(ApplicationManager.java:284)
at com.sap.engine.services.servlets_jsp.server.deploy.impl.WebContainerExtensionContext.getWebModuleContext(WebContainerExtensionContext.java:337)
at com.sap.engine.services.webdynpro.WebDynproRuntimeServiceImpl.start(WebDynproRuntimeServiceImpl.java:380)

Caused by: com.sap.engine.services.deploy.server.utils.DSRemoteException: ASJ.dpl_ds.006153 Error occurred while starting application [sap.com/tc~lm~itsam~co~ui~xi~msg~wd]: It is not started successfully on server nodes [xxxxxxxx]. In order to bring the server in consistent state stop operation will be performed.
Error occurred on server xxxxxxxx during startApp of sap.com/tc~lm~itsam~co~ui~xi~msg~wd : com.sap.engine.services.deploy.exceptions.ServerDeploymentException: Application sap.com/tc~lm~itsam~co~ui~xi~msg~wd cannot be started. Reason: it has hard reference to application sap.com/com.sap.aii.igw.monitoring.ui.app, which is not active on the server because application fails to start with errors. Contact component owners to investigate the problem with application sap.com/com.sap.aii.igw.monitoring.ui.app.
at com.sap.engine.services.deploy.server.LifecycleController.startReferencedApplication(LifecycleController.java:688)
at com.sap.engine.services.deploy.server.LifecycleController.startReferencedComponent(LifecycleController.java:213)

SAP NetWeaver 7.5x SP03

Upgrade, SP03, Message Monitor, NetWeaver Administrator, NWA, Default trace, Entries, Exception, Navigation Parameters, Webdynpro, Services, WDRuntimeException, ComponentUsage, EmbeddedApplicationInst, CreateOnDemand, No active component, ensureActiveComponent, Embedded application, Deployment, Core, ClassLoaderException, Cannot access object, Deployable object, Serverimpl, Repository, XMLPersistence, WCEApplicationNotStartedException, Failed explicit start for application, ApplicationManager, WebContainerExtensionContext, WebDynproRuntimeServiceImpl, DSRemoteException, ASJ.dpl_ds.006153, Starting application, Not started successfully, Consistent state, startApp, ServerDeploymentException, Application, sap.com/com.sap.aii.igw.monitoring.ui.app, Not active, Fails to start, Component owners, LifecycleController, startReferencedApplication, SCA, Dependency, Process Orchestration 7.5, PI 7.5, PO 7.5, XI, AEX , KBA , BC-NWA-XPI , Process Integration (PI) Monitoring , Problem