VC+MO 创建一个新图层失败！大家快来帮帮我吧

<P>以下是我的代码：</P>
<P>CMoDataConnection oConnect; <BR> <BR> CMoTableDesc objTableDesc;//创建新的层的字段结构，新层里除了Shp字段，应该还有一个RoadClass字段<BR> <BR> if (!objTableDesc.CreateDispatch(TEXT("MapObjects2.TableDesc")))<BR> {<BR>  return;<BR> }<BR> <BR> objTableDesc.SetFieldCount(1);<BR> <BR> objTableDesc.SetFieldName(0, "RClass");<BR> <BR> objTableDesc.SetFieldLength(0, 8);<BR> <BR> objTableDesc.SetFieldType(0, 3); <BR> <BR> CString sName("nlayer");//新层的名字<BR>  <BR> CMoDataConnection objDc;<BR> <BR> if (!objDc.CreateDispatch(TEXT("MapObjects2.DataConnection")))<BR> {<BR>  return;<BR> }<BR> <BR> objDc.SetDatabase((LPCTSTR)sOutputpath);<BR> <BR> if (!objDc.Connect())<BR> {<BR>  return;<BR> }<BR> <BR> VARIANT vt;<BR> <BR> VariantInit(;vt);   <BR> <BR> vt.vt = VT_BOOL; <BR> <BR> vt.boolVal =VARIANT_FALSE; </P>
<P> long moShpeTypeLine = 22;</P>
<P> CMoGeoDataset objGds;</P>
<P> if (!objGds.CreateDispatch("MapObjects2.GeoDataset"))<BR> {<BR>  return;<BR> }<BR> <BR>    objGds = objDc.AddGeoDataset((LPCTSTR)sName,moShpeTypeLine,(LPDISPATCH)objTableDesc,vt,vt);<BR> <BR> if (!objGds)//到这里就返回了，objGds没有创建成功，谁能告诉我原因啊！急！！！！<BR> {<BR>  return;<BR> }</P>