The ubuntu 9.10 is not supported by ubuntu community any more. To use apt-get,
you have to manually edit "/etc/source.list" file and replace "archive" with "old-release".
The Opencv 2.3 need a cmake 2.8, buth ubuntu 9.10 only has cmake 2.6, so when you compile the opencv 2.3 the cmake gives you errors and warnings such as "incompletely configuration".
What you need to do is downlad cmake 2.8 and install it.