Need help configure Generate HTTP URL extension

Can anyone please help me configure Generate HTTP URL extension? I have read the extension page but I still not understand how to configure it correctly. I always has error 259 when click on a file, choose Generate HTTP URL.

I want to change ftp://ftp.example.com/myfile.zip to http://www.example.com/myfile.zip
My FTP provider only give me this info ftp.example.com to connect, I don't know my webroot "/home/martin/httpdocs" like in the guide.

Sorry seem I can't post picture. The exactly error is "Command failed with return code 259"

Press Ctrl and Shift, while executing/clicking the Generate HTTP URL.
It copies the command to the clipboard.
Post it here.

With the info I provided above, can you help me what to write in Webroot path, URL Rootpath, Webserver hostname override. So I know that I configure correct before sending you the command. Thanks!

I'm actually interested in seeing the command with your current settings.
With that information I can suggest you what you may have wrong.

I found problem. It was my AV block script, after unblock, it run ok now. Thanks for your help!