This code was much easier to use to copy a file geodatabase feature class. Can't find the source but it was obtained through a google search.
Sub CopyFC(pOldWorkspace As IWorkspace, FCname As String, copyWorkSpace As IWorkspace)
Dim gp As Object
Set gp = CreateObject("esriGeoprocessing.GPDispatch")
Dim pEnumDataset As IEnumDataset
Dim pDataset As IDataset
Dim pFeatClass As IFeatureClass
Dim pEnumFeatClass As IEnumFeatureClass
Set pEnumDataset = pOldWorkspace.Datasets(esriDTFeatureClass)
Set pDataset = pEnumDataset.Next
While Not pDataset Is Nothing
If pDataset.BrowseName = FCname Then
'get FC from pdataset
Dim inFC As IFeatureClass
Set inFC = pDataset
gp.FeatureClassToFeatureClass_conversion inFC, copyWorkSpace, pDataset.BrowseName
End If
Set pDataset = pEnumDataset.Next
Wend
End Sub