[igraph] igraph_is_bipartite error?

[Figa Pelosa]

I installed iGraph on python (PC with ubuntu 9.04) and I have the following error what calling "from igraph import *":

Python 2.5.4 (r254:67916, Apr  4 2009, 17:55:16)
[GCC 4.3.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from igraph import *
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.5/site-packages/igraph/__init__.py", line 30, in <module>
    from igraph.core import *
ImportError: /usr/lib/python2.5/site-packages/igraph/core.so: undefined symbol: igraph_is_bipartite
>>>

Thanks to all
F