Whenever I try to launch 'hotot' I get this errors. This error also appears if i try something stupid in terminal along with "No Module named gdm"

 Error in sys.excepthook:
Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in    apport_excepthook
  from apport.fileutils import likely_packaged, get_recent_crashes
File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 1, in <module>
 from apport.report import Report
File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module>
 from xml.parsers.expat import ExpatError
File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module>
 from pyexpat import *
ImportError: No module named pyexpat

I am on Ubuntu 12.04 python 2.7.3. I found similar problem here https://github.com/Kindari/SublimeXdebug/issues/5 but did not work.

as asked below I am inserting this too

ls  /usr/lib/python2.7/lib-dynload/
audioop.so  _codecs_cn.so       _codecs_jp.so  crypt.so    _ctypes_test.so         _elementtree.so  _io.so      _multibytecodec.so   _sqlite3.so
_bsddb.so   _codecs_hk.so       _codecs_kr.so  _csv.so     _curses_panel.so   _heapq.so        _json.so    _multiprocessing.so  _testcapi.so
  bz2.so      _codecs_iso2022.so  _codecs_tw.so  _ctypes.so  _curses.so          _hotshot.so      _lsprof.so  Python-2.7.egg-info