I successfully installed a similar app, APC Action Apps(http://sourceforge.net/projects/apc-aa). I went through alot of hell to get it to work and had the same kinds of problems (special thanks to SHIN at Dreamhost who gave me some tips for work arounds). APC setup also recycles the same page if register_globals is not set to "On".
Check the PHPNuke site and see if they mention PHPLIB. PHPLIB is a library of little widgets and classes that you need to initially define stuff for object-oriented programmed php scripts (Is this right, folks?) This is probably the big thing your missing. Here's what I did for my apps and how I got around the php.ini file:
Do this by downloading it from http://sourceforge.net/projects/phplib and saving all the files to a folder at the root of your web directory. Then follow their installation instructions, "complete" not "quickstart". "Quickstart" is for people who have access to php.ini.
Here's a tip: In the file prepend.php3 make sure references to your web directory start with "/home". This is the location of your web files specific to Dreamhosts local machine. (you'll probably see this come up in error messages...).
around the OPEN_BASEDIR RESTRICTION[/b]
I'm not sure if you've already run into the open_basedir restriction:
You'll need to create a text file called .htaccess and put this in it to make your PHP scripts act like cgi scripts (users on Dreamhost are only allowed to execute cgi scripts):
AddType php-cgi .php .php3
You should place this file at the top of directories where there are any php or php3 files. It'll take care of everything for you.
you've installed PHPLIB...[/b]
Read this handy note which I found on the FAQs (http://apc-aa.sourceforge.net/faq/#458) page for the apps I installed, which addresses the php.ini file:
"I have limited access to my box, how do I access PHPLIB?
If you are unable to edit php.ini, then you won't be able to change the include path to point at PHPLIB, in this case edit the config file (yours may be called config.php) to add the following lines.
PHPlib directory if not on include path
$_PHPLIB["libdir"] = "/www/mysite/phplib/php/";
Change the site to point at the location where you have installed phplib.
You can also access PHPLIB by putting the following line in your .htaccess
php_value include_path ".:/usr/local/lib/php:/usr/local/lib/php/phplib"
So as I said it was a really crazy installation (and I ended up reading alot of installation documentation). But it all works now!
I hope this helps, or at least gets you on the right path.