[galaxy-dev] Error running set_dataset_sizes.py

Hello, I'm seeing some discrepancies in total user usage versus what my histories actually total so I wanted to run set_dataset_sizes.py and set_user_disk_usage.py I am getting the following error. ./set_dataset_sizes.py Loading Galaxy model... Processing 77915 datasets... Completed 0% Traceback (most recent call last): File "./set_dataset_sizes.py", line 43, in <module> dataset.set_total_size() File "lib/galaxy/model/__init__.py", line 703, in set_total_size if self.object_store.exists(self, extra_dir=self._extra_files_path or "dataset_%d_files" % self.id, dir_only=True): AttributeError: 'NoneType' object has no attribute 'exists' Any help would be much appreciated. Thanks, Liisa