hi everyone here! i have the following error

Nokia-N900-02-8:/# mypaint
Traceback (most recent call last):
File "/opt/mypaint/bin/mypaint", line 123, in <module>
from gui import main
File "/opt/mypaint/share/mypaint/gui/main.py", line 11, in <module>
import gtk, hildon, osso
ImportError: No module named osso
Nokia-N900-02-8:/#



how can i fix it??