AttributeError: 'NoneType' object has no attribute 'nodeValue'

I am using Gtg 0.1.2 from the ppa on jaunty. I created a task which is not modifiable any more. When I try to modify it, I get the following console output :

Traceback (most recent call last):
  File "/var/lib/python-support/python2.6/GTG/taskeditor/taskviewserial.py", line 155, in unserialize
    success = self.parsexml(content_buf,ite,element.firstChild) #pylint: disable-msg=E1103
  File "/var/lib/python-support/python2.6/GTG/taskeditor/taskviewserial.py", line 204, in parsexml
    text = n.firstChild.nodeValue
AttributeError: 'NoneType' object has no attribute 'nodeValue'
Traceback (most recent call last):
  File "/var/lib/python-support/python2.6/GTG/taskbrowser/browser.py", line 1355, in on_edit_active_task
    self.open_task(tid)
  File "/var/lib/python-support/python2.6/GTG/taskbrowser/browser.py", line 1122, in open_task
    notes=self.notes)
  File "/var/lib/python-support/python2.6/GTG/taskeditor/editor.py", line 143, in __init__
    self.textview.insert("%s"%texte)
  File "/var/lib/python-support/python2.6/GTG/taskeditor/taskview.py", line 217, in insert
    self.buff.deserialize(self.buff, self.mime_type, _iter, text)
glib.GError: Une erreur inconnue est survenue lors de la tentative de décodage de application/x-gtg-task

Steps to reproduce :
1. Create a new task using the form
2. Insert at least 2 subtasks by starting the line with a “-”
3. Remove the last arrow with either backspace or enter
4. Skip a line
5. Insert a tag

What I see here :
* Whatever I type after step 3. gets the same style as subtasks
* The skiped line creates an empty subtask
* The tag inserted at step 5. generates a subtask with the tag as name
* If I do not skip a line, then try to modify the main task, I see that the tag is repeated with an arrow at the left, on the (new) last line. Then after closing the task I cannot open it anymore
* If I insert simple text instead of a tag, a subtask with that text is created + the text appears twice in the description of the main task (first without then with an arrow at the left)