Problem editing kindle collections

[piperclassique]

I got this when trying to manually edit kindle collections in Calibre. Using a jailbroken paperwhite with collections manager, latest calibre build, windows 7 64 bit.

Anyone know what it means? I'm not very techie myself.......
Came up as soon as I clicked edit collections manually

calibre, version 1.7.0
ERROR: Unhandled exception: <b>UnicodeDecodeError</b>:'utf8' codec can't decode bytes in position 62-63: invalid continuation byte

calibre 1.7 isfrozen: True is64bit: False
Windows-7-6.1.7601-SP1 Windows ('32bit', 'WindowsPE')
('Windows', '7', '6.1.7601')
Python 2.7.5
Windows: ('7', '6.1.7601', 'SP1', 'Multiprocessor Free')
Traceback (most recent call last):
File "calibre_plugins.kindle_collections.ui", line 165, in edit_kindle_collections
File "calibre_plugins.kindle_collections.kindle_edit_co llections", line 75, in run
File "calibre_plugins.kindle_collections.kindle_edit_co llections", line 92, in __init__
File "calibre_plugins.kindle_collections.kindle_edit_co llections", line 112, in init_sort_order
File "calibre_plugins.kindle_collections.kindle_edit_co llections", line 307, in get_sorted_paths
File "calibre_plugins.kindle_collections.kindle_boo ks", line 523, in get_sorted_paths
File "calibre_plugins.kindle_collections.kindle_sor t", line 66, in sort_names
File "calibre_plugins.kindle_collections.kindle_sor t", line 139, in sort_compare_kindle_names
UnicodeDecodeError: 'utf8' codec can't decode bytes in position 62-63: invalid continuation byte

Edit to add. I tried again and Calibre seemed to accept the edit, but then it didn't show up on the kindle after eject and restart.