如何创建coverage下的featureclass?

 打开一个coverage,付给IFeatureDataset,调用IFeatureDataset的CreateFeatureClass，报错：对象不支持该方法，很奇怪，谁帮帮我？？为什么错？怎么修改？
<P>Dim pWorkspaceFactory As IWorkspaceFactory<BR>    Dim pWorkspace As IWorkspace<BR>    Dim pFeatureWorkspace As IFeatureWorkspace<BR>    Dim pFeatCls As IFeatureClass</P>
<P>    Set pWorkspaceFactory = New ArcInfoWorkspaceFactory<BR>    Set pWorkspace = pWorkspaceFactory.OpenFromFile(frmVctToCoverage.strW, 0)<BR>    Set pFeatureWorkspace = pWorkspace<BR>    Dim pFeatDSet As IFeatureDataset<BR>    Set pFeatDSet = pFeatureWorkspace.OpenFeatureDataset(frmVctToCoverage.strD)</P>
<P>   ...............</P>
<P>Set pFeatCls = pFeatDSet.CreateFeatureClass("he", pFields, pUID, Nothing, esriFTSimple, strshape, "</P>
<P>拜托~~~~~~~~~~~~~~<BR></P>

<P>打开函数里面的字符串参数没用引号！</P>