请问这个分割页面程序问题在哪儿

学习中，按书上的来，编译链接都没问题，运行时总出来什么assert failure，请问这是什么意思？CRect rect;
GetWindowRect(&rect);
if(m_splitter1.CreateStatic(this,2,1)==NULL)
return FALSE; m_splitter1.CreateView(0,0,RUNTIME_CLASS(CTestViewControl),CSize(rect.Width()/2,rect.Height()/2),pContext);
//m_splitter1.CreateView(0,0,RUNTIME_CLASS(CTestViewPicture),CSize(800,600),pContext);
if(m_splitter2.CreateStatic(&m_splitter1,1,2,WS_VISIBLE|WS_CHILD,m_splitter1.IdFromRowCol(1,0))==NULL) m_splitter2.CreateView(0,0,RUNTIME_CLASS(CTestViewPicture),CSize(rect.Width()/2,rect.Height()/2),pContext);
m_splitter2.CreateView(0,1,RUNTIME_CLASS(CTestViewDown),CSize(rect.Width()/2,rect.Height()/2),pContext);
return TRUE;