Problem libpython2.3.so.1.0

Hello,

I am not experienced PostgreSQL user but have following problem:

I am unable to use plpythonu on linux (ubuntu 9.04). After I execute
command:

psql# CREATE LANGUAGE plpythonu;

I got following error message:

ERROR: could not load library
"/opt/PostgreSQL/8.4/lib/postgresql/plpython.so": libpython2.3.so.1.0:
cannot open shared object file: No such file or directory

I usually use python2.6.2...

P.S. I can do that on windows,but I am not fan on it.

Best regards,
Predrag