If you followed the manual line by line you would see that in 2) the first two lines differ.
should be replaced by:
And in 3) I cannot see that you load the jk_module
LoadModule jk_module /usr/lib/apache2/modules/mod_jk.so
Try to take some time and check again the manual line by line copying and pasting the commands and if it does not work then get back here.
And since you are using httpd.conf this means you are not using Debian 3.1 so it might be a problem with your distro. In Debian we use apache2.conf for the configuration file.