Programmtically deleting a geometric network in ArcCatalog and then deleting the network's feature dataset, will cause ArcCatalog to fatal.
This is a known issue.
Solution or Workaround
There are two workarounds for this problem:
- Do not delete the feature dataset following this operation. Close and re-start ArcCatalog to delete the dataset.
- Delete the network using IGxObjectEdit:Delete instead of Dataset:Delete. In ArcCatalog, get a reference to the selected object from IGxApplication:SelectedObject and QI to IGxObjectEdit