Porting from CS4 to CS5, save document failed.

Question

I am porting programes from CS4 to CS5, and meet a problem.
In my program I need delete some page from a indesign document and then save it back.
I open the document use the code below
InterfacePtr<IK2ServiceRegistry>    serviceRegistry(Porting::GetPointerToSession(), UseDefaultIID());
        ASSERT(serviceRegistry);
        if (!serviceRegistry)
            break;
        InterfacePtr<IK2ServiceProvider> openManagerService(serviceRegistry->QueryDefaultServiceProvider(kOpenManagerService));
        ASSERT(openManagerService);
        if (!openManagerService)
            break;
        InterfacePtr<IOpenManager>  openManager(openManagerService, IID_IOPENMANAGER); // no kDefaultIID
        ASSERT(openManager);
        if (!openManager)
            break;
        UniFile fileDocument = fTemplateCopyFile;
        UIDRef DocumentRef = openManager->OpenDocFromFile(&fileDocument,kFullUI);
and then delete some page
for( int i = 0; i < fnPageCountOfCopy; ++i )
            UID idPage = fvPageUID[i];
            if ( fPageIDList.DoesNotContain(idPage) )
                UIDRef refPageToDelete( fTemplateCopyUIDRef.GetDataBase(), idPage );
                InterfacePtr<ICommand> deleteCmd(CmdUtils::CreateCommand(kDeletePageCmdBoss ));
                if( deleteCmd )
                    UIDList tempList(refPageToDelete);
                    deleteCmd->SetItemList( tempList );
                    ErrorCode status = CmdHelper::ProcessCommand( deleteCmd );
then save it back
pOldHandler->SaveAs(fTemplateCopyUIDRef,
            &fTemplateCopyFile,
            K2::kSuppressUI,
            kFalse,
            kInDesignFileTypeInfoID);
but save failed. The code works on CS4, but does not work on CS5.
Does anybody know why? Any suggestion is appreciated.

Answer 1

I found that delete operation will affect save operation, but I don't know why and how to solve it.
Is it a threading problem?