Fatal error: Class 'CI_Controller' not found

[eluser]melba[/eluser]
Hello Im using a script named rbs 1.2 of cogzidel and that happens to be a bid script and it all works properly the only thing is that it dont get back to my site after purchase,so I went and I added in paypal my ipn url and it got me this error:
Fatal error: Class 'CI_Controller' not found

Firstly I know the url I added on ipn paypal is the right one because the code of the page has the following:
class Login extends Controller {

public $outputData;
public $loggedInUser;

/**
* Constructor
*
* Loads language files and models needed for this controller
So it never speaks about CI,can I install the missing controller via ssh?
Really would like to know where to alter the file,but if is better installing the controler via ssh,please give me some feedback bros

----and it also makes reference to this:
paypalIpn()

So... I know I need the ci class controler but I dont know how to install it,could you please try to answer this questions?:

1-Where I upload the code igniter files after unzipping,is it on my home root,or is it on my rbs script?

2-After uploading the files in the right place how do I run the installation of codigniter on my server?,can it be via ssh,or by hitting an install file?

3-Can I install ci class controller independently?

Since the cogzidel forum is so snobby they dont allow me to register and I cant solve this issue from there,but the error from paypal is diferent from the error of hitting the payment file directly that is:
Fatal error: Class 'Controller' not found in /home/admin/melba/bidscript/app/controllers/payment.php on line 8

Please give me a hint in order to know if is just a line of code I need ,or do I need to install code igniter,or maybe the return url is not the righteous.

[eluser]vrencianz[/eluser]
Maybe

Code:

class Login extens CI_Controller {

and installation instructions

helps?

[eluser]melba[/eluser]
Thank you now that you mention the error line 8 is where this code dwells:
class Login extends Controller {
so it makes sense what you say and putting that instead,but..........
are you sure is
class Login extens CI_Controller {
or..............
class Login extends CI_Controller {
?

[eluser]melba[/eluser]
I did as you say but I get almost the same error
Fatal error: Class 'CI_Controller'not found in /home/admin/melba/bidscript/app/controllers/payment.php on line 8

[eluser]CodeIgniteMe[/eluser]
What is your CI version?

[eluser]melba[/eluser]
Please read the post because I already stated Im not sure how to install Code Igniter

because my script cant have code igniter already installed in it or does it?,because Ive seen tons of pages with code igniter notes on it

Thank you

[eluser]CodeIgniteMe[/eluser]
You really need help on Installing Codeigniter.
Please read the userguide first to get started on CI

Thanks

[eluser]melba[/eluser]
I made questions regarding this but you didnt read op's post
CodeIgniter is installed in four steps:
Unzip the package.
Upload the CodeIgniter folders and files to your server. Normally the index.php file will be at your root.
Open the application/config/config.php file with a text editor and set your base URL. If you intend to use encryption or sessions, set your encryption key.
If you intend to use a database, open the application/config/database.php file with a text editor and set your database settings.

If you wish to increase security by hiding the location of your CodeIgniter files you can rename the system and application folders to something more private. If you do rename them, you must open your main index.php file and set the $system_folder and $application_folder variables at the top of the file with the new name you've chosen.

For the best security, both the system and any application folders should be placed above web root so that they are not directly accessible via a browser. By default, .htaccess files are included in each folder to help prevent direct access, but it is best to remove them from public access entirely in case the web server configuration changes or doesn't abide by the .htaccess.

After moving them, open your main index.php file and set the $system_folder and $application_folder variables, preferably with a full path, e.g. '/www/MyUser/system'.

One additional measure to take in production environments is to disable PHP error reporting and any other development-only functionality. In CodeIgniter, this can be done by setting the ENVIRONMENT constant, which is more fully described on the security page.

That's it!

[eluser]melba[/eluser]
please read my number questions I dont know where to upload files,in home or in my script?

[eluser]CodeIgniteMe[/eluser]
In your web root home.