firefox browswer

I am receiving an error code wiping slack space. what does it indicate?

File "bleachbit\GUI.pyo", line 593, in cb_wipe_free_space
File "bleachbit\GuiBasic.pyo", line 40, in browse_folder
File "bleachbit\Windows.pyo", line 123, in browse_folder
pywintypes.com_error: (-2147467259, 'Unspecified error', None, None)

John