It looks like you are running python-sip4 from a backports repository.
Is that correct?
Karmic version: http://packages.ubuntu.com/karmic/python-sip4
I would install apt-show-versions and then checkout what python-sip4 packages you can install from the various repositories you have configured:
apt-show-versions -a python-sip4
Then try installing the core Karmic version that is listed in the apt-show-versions output:
aptitude install python-sip4=4.9.1-snapshot-20091015-0ubuntu1
Unfortunately this may cause even more problems, especially if you are using packages from the backport repository which requires the newer version of python-sip4.
Plus, the next time you run apt-get upgrade it will probably want to upgrade to python-sip4 4.10. Therefore you'll either need to remove the backports repository, or put a lock on the version you've currently got installed.
Your best bet would be to remove any third party repositories you have installed, revert your installation back to something that is 'pure' Karmic, and move forward from there:
(This article refers to Debian, but it is equally applicable to Ubuntu)