pylab import problems

Just installed FC6 onto AMD 64 bit processor and have

    > installed Python. I have also installed numpy and
    > matplotlib however when I run IPython and begin importing
    > items I run into a problem when try to import pylab.
    > Specifically I receive the following dump:

    > ImportError: No module named _ns_backend_gdk

    > I am new to this and would appreciate any help in resolving
    > this problem. Thanks.

this looks like numpy was not available at compile time. Make sure
you have a compatible numpy and mpl (eg the latest release of both or
the latest svn of both) and then do a clean build (eg 'rm -rf build').