Getting "*** failed to import extension" errors after upgrading to 1.5.1

[Pavel Shevaev]

> did you try to import hgext.purge from a python prompt?

Hm...it gives the following:

Python 2.6.4 (r264:75706, Dec  7 2009, 18:45:15)
[GCC 4.4.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import hgext.purge
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named purge

At the same time:

>>> import sys
>>> print sys.path
['', ... '/usr/local/lib/python2.6/dist-packages']

and:

>>> import hgext

...works just fine and there is
/usr/local/lib/python2.6/dist-packages/hgext/purge.py

I'm a bit lost :(

-- 
Best regards, Pavel