I have resolved my own issue. For anyone who comes along after me:
- Use FileZilla as FTP. I used FTP Commander, and that seemed to be the root of my problems - I think it was dropping files
- If you can install in your final destination directory, go ahead and do so instead of going through the headache of migrating.
Here's how I fixed it:
- I backed up my SQL database. I am a newbie, so I muddled through this. I stumbled into PHPmyadmin. I did this through the SQL databases feature in my webhost's cpanel. There is a function to copy a database. I was able to export a backup as a text file on to my desktop.
- If you haven't already, also copy all of your existing joomla files on to your hard [drive] - we know these are kind of tanked, but I was able to manually put some things back in from these files.
- I then uninstalled Joomla through my Fantastico on my webhost. This will wipe Joomla and your SQL database (hence the need for the backup....). I also cleared out pretty much everything from my public_html directory to avoid any conflicts from old files etc. - a clean slate.
- I then reinstalled Joomla into my main directory. In my case I just left the directory field blank. I created a user password etc.
- Joomla now worked as it had at my very first beginning. My next step was to try to link it back to my old data in the SQL database.
- I went back into my SQL database on cpanel. I created a new database, and a new user, and applied the new user to the new database.
- I then opened the database I had just created and imported the data from my exported text file on my desktop.
- Then I went in to the configuration.php file and changed:
var $user = 'newusername';
var $password = 'newpassword';
var $db = 'newSQLdatabasename';
where the existing fields will represent the new joomla database that was created during the intsall. I changed these to the database and username I had just created.
When I went to preview, my site data was generally back up - just using the default template.
At this point, I was able to start copying back in some files from my Joomla files back up. For example, I copied my entire specific template file into the templates folder on the server. Immediately my template was applied. This meant I did not have to reinstall the template and reconfigure. I could just copy the files into the appropriate directories. Same thing for modules etc.
I found this post helpful for understanding this rebuild process: viewtopic.php?p=1417076
I hope someone else finds this useful. I spent 4 or 5 hours trying to find a solution to the error I was getting, and about 20 minutes rebuilding everything and linking to the old data.....