I am bumping this because after a couple of years I have run into the exact same problem.
Now it shows from step two:
PHP CLASSIFIEDS INSTALL
Step 1 >> Step 2 >> Step 3 >> Step 4
This is all it shows. So I am not seeing the database results and I know the information I am using is correct.
But, it happens even when I do not enter any information and just click next.
I have tried anything from chmodding files and directories, using htaccess files and modifying my php.ini file.
What I noticed is that the script does work on a server with a different PHP version.
But I am not sure if this has anything to do with it. It's just this part that won't show.
O, and I forgot how it was solved before