I've tried both on my computer and on my paid hosting service. The errors I posted were on my hosting service.

Umm that's so strange, as far as I know the script runs on most webhosts, the class not found error u posted was honestly the very first time I've ever heard of. If u don't mind, please do keep testing the script on ur server and lemme know if u find out why the script ain't working on ur webhost. I'd be curious to find out the cause of this error.

When i enter my host user and password on filezilla that i got from ooowebhost, it says it can't connect to the server

First - you're not using "localhost" as the host, correct?

That web host has a page for their FTP program, I can't remember exactly where on the page. It should have all of your details, double-check that you're entering the correct details.

What is the exact message you're getting when it doesn't connect? Is it saying it can't find the server, there are too many connections...?

it shows 2 errors. error: connection timed out and error: Could not connet to server.
I followed the deirections. It game me this information:

MySQL database will be created in 1 minute. Use these details for your PHP scripts:

$mysql_host = "host";
$mysql_database = "database";
$mysql_user = "user";
$mysql_password = "password";

I changed the values for this post, but I used the actual values on filezilla. I was also sent an email with account details and file upload details. All of these showed the same error messages.

the upload details contained FTP hostname, username, and password. That didn't work either.

Please edit your post instead of double posting.

With the ones you posted, those are your mySQL details, not your FTP details.

MySQL is your database, it resides on your server and is used to store information. You'll need that for installing the script. FTP stands for "Files to Program", if I remember correctly, and is a remote way to access your file manager. Only your FTP details can be put into filezilla.

I'm signing up for 000webhost to see if I can find your details easier.

Oh thank you so much. Turns out I was using the wrong password... sorry for the inconvenience!

Alright, that's good to hear! Tell us if you have any more questions~

It's "File Transfering Protocol". Just like HTTP is "Hypertext Transfer Protocol". Web is all protocol based, so every "TP" is most likely a transfer protocol