求助：加载sde数据出错？

Public Function addSDEData(ByVal Server As String, ByVal Instance As String, ByVal User As String, _
ByVal Password As String, ByVal featureClass As String, Optional ByVal version As String = "SDE.DEFAULT")
On Error GoTo EH

Dim pWorkspaceFactory As ESRI.ArcObjects.Core.IWorkspaceFactory
Dim pWorkspace As ESRI.ArcObjects.Core.IFeatureWorkspace
Dim pPropSet As ESRI.ArcObjects.Core.IPropertySet
Dim pClass As ESRI.ArcObjects.Core.IFeatureClass
Dim pFeatureDataset As ESRI.ArcObjects.Core.IFeatureDataset
Dim pLayer As ESRI.ArcObjects.Core.IFeatureLayer
Dim pMxDoc As ESRI.ArcObjects.Core.IMxDocument

pWorkspaceFactory = New ESRI.ArcObjects.Core.SdeWorkspaceFactory
pPropSet = New ESRI.ArcObjects.Core.PropertySet

With pPropSet '设置ArcSDE连接属性
.SetProperty("SERVER", Server)
.SetProperty("INSTANCE", Instance)
.SetProperty("USER", User)
.SetProperty("PASSWORD", Password)
.SetProperty("VERSION", version) '可选，缺省为SDE.DEFAULT版本
End With

pWorkspace = pWorkspaceFactory.Open(pPropSet, 0)
'pFeatureDataset = pWorkspace.OpenFeatureDataset(featureClass)
pClass = pWorkspace.OpenFeatureClass(featureClass)


pLayer = New ESRI.ArcObjects.Core.FeatureLayer
pLayer.FeatureClass = pClass
pLayer.Name = pClass.AliasName


pLayer.Visible = True
AxMapCtrol.AddLayer(pLayer)


Exit Function
EH:
MsgBox(Err.Description, vbInformation, "加载数据错误")
End Function
有两个问题:
1运行到最后一句AxMapCtrol.AddLayer(pLayer)时报错"未将对象引用设置到对象的实例"
2如果我需要加载的是FeatureDataset,该怎么办?
请大虾们指导!!!

<P>未将对象引用设置到对象的实例</P><P>可能是你图层名字格式写错了吧</P>

<P>能说具体一些吗？？我传的变量featureclass肯定是正确的，因为</P><P>pClass = pWorkspace.OpenFeatureClass(featureClass)没有出错</P><P>我认为是add方法出错了，但是我试了好多都不行！！
</P>

晕了，还有没有人能解决这个问题？？

已经解决此问题！