Cannot Complete Basic/Initial Installation of Gallery3

I have not been successful in installing Gallery3, at least to the point where I could begin adding images. I have downloaded the installation archive, put it in the public_html directory of my web site, added the /var directory (with 777 attributes) to the root directory, and added a new MySQL database for Gallery3. At that point what URL am I supposed to use? Any idea of what I could be doing wrong? Thanks.

When I do that, it takes me to:

http://www.iana.org/domains/example/

I know that's just an example you're trying to provide. Can you be explicit with your instructions please? For example, should, "example.com", be my web site domain name? Thanks.

Okay, found and corrected one problem, but then discovered another. I had my Gallery3 distribution in the wrong directory of my web site folders, and fixed that. Now, when I go to:

http://marlowheights60sand70s.com/gallery3/installer/index.php

it is telling me that my php.ini file needs to have short_open_tag set to on. It is, at least where it's supposedly mirrored, which is the .htaccess file. What do I need to change? Thanks.

This is what my hosting provider (InMotion Hosting) said in response to your
suggested fix:

"I have reviewed your php.ini file and short_open_tag = On. I have made no
modifications to your file. This was always the case. There may be another
issue that is preventing installation. Please review your installation
documentation and we can try to assist further. In order to assist further,
we will need you to verify the account with either the AMP password or the
last four digits of the credit card we have on file."

Looks like I'm back to square one. Any suggestions? Otherwise it seems like I'm stuck between one entity pointing the blame at the other, and nothing gets accomplished.

Thanks!

I apologize for not comprehending, but I wouldn't give anyone access to my protected directories. If it's this phpinfo.php file you need, tell me how to create it and possibly I can attach it here. The only thing I have in my gallery3 directory now is a php.ini file.

http://marlowheights60sand70s.com/gallery3/installer/

Is that sufficient? Please remember that some of us aren't web developers by profession (I'm actually a Security Engineer), so what may be obvious or intuitive to you, isn't necessarily so for some of us. But thank you for at least responding.

Okay, sorry for being so dense. The phpinfo.php file is now there:

http://marlowheights60sand70s.com/gallery3/phpinfo.php

Thanks.

Hate to be so dense AGAIN, Dave, but where am I supposed to copy the installer.php file to? In the root of my gallery3 directory, or the installer directory under the gallery3 root? And after I do that...what next?

I did as instructed, yet that same, "Whoa there!", error message comes up. I can't believe I've been piddling around with something like this for two weeks, and it STILL doesn't work. Don't get me wrong, I do appreciate your help. But quite frankly I need something that works right out of the box and allows me to start setting up photo galleries on my web site. Forget open source, I don't mind paying for an application that will do what I need it to do. Not very impressed so far with Gallery, due to the difficulty in what should be a very simple installation.