请高手给看看下面的代码有什么问题，MAPX5.0＋VC

Question

void drawNewFeature(
 const CString &csLayerName, 
 double dblLng, 
 double dblLat,
 const CString &csName,
 const CString &csLevel,
 const CString &csTime
 )
{
CMapX *m_mapx;
CMapXStyle pStyle; pStyle.CreateDispatch(pStyle.GetClsid());
pStyle.SetSymbolType(miSymbolTypeVector);
pStyle.SetSymbolCharacter(34);
pStyle.SetSymbolVectorSize(16);
pStyle.SetSymbolVectorColor(miColorRed);

CMapXLayer  pLayer;
pLayer = m_mapx->GetLayers().Item(csLayerName);

pLayer.BeginAccess(miAccessReadWrite);

{
m_mapx->SetAutoRedraw(FALSE);
pLayer.SetEditable(TRUE);

CMapXFeature pFeature;
CMapXPoint pPoint;
CMapXFeatureFactory pFeatureFactory; pFeatureFactory = m_mapx->GetFeatureFactory();
pFeature.CreateDispatch(pFeature.GetClsid());
pPoint.CreateDispatch(pPoint.GetClsid());

pPoint.Set(dblLng,dblLat);

VARIANT vtPoint;
VARIANT vtStyle;

vtPoint.vt = VT_DISPATCH;
vtPoint.pdispVal = pPoint.m_lpDispatch;

vtStyle.vt = VT_DISPATCH;
vtStyle.pdispVal = pStyle.m_lpDispatch; pFeature = pFeatureFactory.CreateSymbol(vtPoint, vtStyle);
pLayer.AddFeature(pFeature.m_lpDispatch); pLayer.Refresh(); pLayer.SetKeyField("name");
pFeature.SetKeyValue(csName);
//find error here
pFeature.Update(); pLayer.SetKeyField("level");
pFeature.SetKeyValue(csLevel);
pFeature.Update(); pLayer.SetKeyField("time");
pFeature.SetKeyValue(csTime);
pFeature.Update(); m_mapx->ZoomTo(1000,pFeature.GetCenterX(),pFeature.GetCenterY());

m_mapx->SetAutoRedraw(TRUE);
pLayer.SetEditable(FALSE);

m_mapx->Refresh();
} pLayer.EndAccess();  
}