[Extension Installer] - Fatal Error

Good afternoon

- I have installed Opencart version 2.3.0.2 as of today.
- I bought an extension from the Marketplace
- I have set up my FTP credentials under Settings
- I go to Extension Installer and press Upload and choose the file: 'install.ocmod.zip'
- I get an error

Error Message - Uploaded on Imgur:

http://imgur.com/bHoQZp9

Questions

Question 1 - Is the following FTP issue related to this error?

At the FTP Settings there is a text field named 'FTP Root' with a questionmark. When I mouse over that questionmark says: 'The directory your opencart installation is stored in. Normally public_html.

My opencart installation is stored in www.nameofmycompany.be/webshop which is not the FTP Root. As there are several other folders in the root. The 'webshop' folder is just one out of many. What is the exact info that must be placed in here? I have tried the following combinations and the given error above is still persisting.

I entered:

public_html
http://www.nameofmycompany.be/webshop
http://www.nameofmycompany.be
www.nameofmycompany.be
nameofmycompany.be
www.nameofmycompany.be/webshop

and

nameofmycompany.be/webshop

Question 2 - If these are separate things, what is the correct info for FTP Root?

Question 3 - What is the meaning of this error? And how to fix it?

Note: I can access my website with Filezilla, and have set all folders/subfolders and documents to 0755, my FTP login credentials are working fine when used in Filezilla.

Note 2: The owner of the addon says my addon is not compatible with the current version of Opencart (2.3.0.2) but that he has a backwards compatibility mod available.

Note 3: Even the vqmod cannot be installed with the Extension Installer, giving the same error.

Note 4:

OS: Windows 10 Home, 64-bit
Browser: Mozilla Firefox 52.0.2 (32-bits)
OpenCart Version: 2.3.0.2
Extensions to be 'yet' installed: vqMod and Advanced Shipping Pro

I have followed all install.txt files and read them with highest precaution. The error is currently blowing my mind to a higher level than anyone can imagine. I feel unbelievable dumb at this very moment. Any help would be greatly appreciated.

If any other information / action is needed in order to help me, just ask and I'll come back with the refined results.

With most kind regards
Thylbert

To determine the initial path, login to ftp using that account with filezilla or some program... and see where you start out. If you start out in your home and you see folders like "public_html", "public_ftp", etc.. then you need to put "public_html/" in that field
If you start out looking directly at the opencart folder, then you only need to put "/" in that field

I've never seen that error. You can try a bad password and you should see a different error about being unable to login.

Be sure your server uses plaintext ftp as I don't believe opencart yet supports sftp or ftps.
Ultimately you may need to hire someone to log in and look into it on your host as that isn't a normal issue.

Hello again

"To determine the initial path, login to ftp using that account with filezilla or some program... and see where you start out. If you start out in your home and you see folders like "public_html", "public_ftp", etc.. then you need to put "public_html/" in that field
If you start out looking directly at the opencart folder, then you only need to put "/" in that field"

My webserver (One.com) does not use folders like public_html and public_ftp. All I see is an empty root with many folders. One of these folders is called 'Webshop' so I do not start looking directly into the opencart folder nor do I see any public_ folders at all.

What is the initial path then?

Image of my Filezilla whilst logged in: http://imgur.com/a/oisX3

--

Note 1: I entered a false password and the error code is exactly the same as previously linked above. Isn't it a tiny odd that I get an error none have seen before? I mean surely it has a meaning and a solution, no?

Note 2: I have now re-installed the entire software 7 times. Every time it was succeeded without any difficulties, yet every of these 7 times gave me the exact error when trying to install an extension via the extension manager.

Last Note: I do hope somebody can help me out. It's kinda frustrating when you buy software (legit extension from the Opencart Marketplace) and that this extension by all means is not installable. I've seen the beauty and the strengths of Opencart and that's the sole reason I want to use it. It has a nice community, good extensions and it would be great to get things sorted.

Edit: "Be sure your server uses plaintext ftp as I don't believe opencart yet supports sftp or ftps." I'm fairly new, is there a way for me to check out wether I am - or not am - using plaintext ftp?

Edit 2: I asked One.com over chatsupport and I am using plaintext FTP, the possibility for SFTP is available but it's turned off.

With most kind regards
Thylbert