Message Window: "Program Failure discovered" when copying bookmarks in Nautilus

In Dapper, the following message occured when I tried to copy two files (bookmarks.html and bookmarks.bak from another firefox profile, firefox not running while doing this) with nautilus (which worked):

Programmfehler entdeckt
Es wurde ein Fehler im Programm entdeckt
Möglicherweise ist dieser nicht schwerwiegend, sollte aber trotzdem den Entwicklern mitgeteilt werden. Das Programm kann sich von nun an ungewöhnlich verhalten.

(Translated by me:
Program failure discovered.
A failure in a program is found. Maybe it is not a major problem, but it should be told to the developer. The program may behave strange from now on.)

Details:
Traceback (most recent call last):
  File "/usr/lib/deskbar-applet/handlers/mozilla.py", line 153, in <lambda>
    self.watcher.connect('changed', lambda watcher, f: self._parse_bookmarks())
  File "/usr/lib/deskbar-applet/handlers/mozilla.py", line 161, in _parse_bookmarks
    self._bookmarks, parsed_file, self._shortcuts_to_smart_bookmarks_map = MozillaBookmarksParser(self).get_indexer()
  File "/usr/lib/deskbar-applet/handlers/mozilla.py", line 257, in __init__
    self.close()
  File "/usr/lib/python2.4/HTMLParser.py", line 112, in close
    self.goahead(1)
  File "/usr/lib/python2.4/HTMLParser.py", line 164, in goahead
    self.error("EOF in middle of construct")
  File "/usr/lib/python2.4/HTMLParser.py", line 115, in error
    raise HTMLParseError(message, self.getpos())
HTMLParseError: EOF in middle of construct, at line 87, column 21

I haven't found a strange behaviour yet, but wanted to report this anyway.