On some servers, when you're trying to upload new extension via OpenCart Extension Installer, you get error:
<b>Warning</b>: ftp_nlist(): listen() faled: Operation not permitted (1) in <b>..............
The solution of this issue is to change ftp-connection to passive mode.
This extention does exactly this thing.
Installation very simple:
1. Place the file 'ocmod_upload_error_fix.ocmod.xml' into your system folder.
2. Go to the Admin section -> Extensions -> Modifications and click button 'Refresh' on the top right corner.
Here's little video of the error and the solution: