You have to entertain the idea that one or the other of the (empty) files in Trash has characteristics/content that your computer refuses to delete (because doing so might cause irreparable harm to your system).
This may actually be the answer. The original post did not specify the items, just that they were part of the package contents. To me, that in itself is a risky process. Why not just delete the entire widget package? The remaining items may be, in some unknown way, System components.
