If you're using a binary version, it may require a more recent version of libc, a version your Ubuntu doesn't come with.
One thing you could try is to compile Code::Blocks from source code. The steps to do that are in the Wiki.
Another thing you could try is to upgrade your Ubuntu distribution to Edgy or Feisty, or try running sudo apt-get dist-upgrade (be sure to run sudo apt-get update first).