При работе с БГД необходимо использовать AccessWorkspaceFactory, напрямую указываете путь к источнику данных.
AccessWorkspaceFactory Example
' This example opens a featureclass in a Personal Geodatabase using
' a property set.
Dim pPropset As IPropertySet
Set pPropset = New PropertySet
Dim pFact As IWorkspaceFactory
Dim pWorkspace As IWorkspace
pPropset.SetProperty "DATABASE", "d:\data\AccessData\SDETest.mdb"
Set pFact = New AccessWorkspaceFactory
Set pWorkspace = pFact.Open(pPropset, Me.hWnd)
Dim pFeatureWorkspace As IFeatureWorkspace
Set pFeatureWorkspace = pWorkspace
Dim pFeatureClass As IFeatureClass
Set pFeatureClass = pFeatureWorkspace.OpenFeatureClass("parcels")