Beep boop, I’m a bot! I dug through the forum to get you started. I sometimes get things wrong though, so do with this what you will until a human has a look.
Short answer: on our hosting, PHP code can’t access files outside the htdocs directory of the website it runs on, so I don’t think the open_basedir setting can be changed. The OpenCart guide says that’s why OpenCart’s data directory has to sit inside htdocs, for example htdocs/ocartdata instead of the default ocartdata.
Here’s the guide:
It’s written for the Softaculous installer. Your warning wants access to the folder above htdocs, so it looks like the installer is trying to use a storage or data location outside htdocs. A solved topic with a similar manual-install warning had the same cause, a data path outside htdocs:
Are you installing manually or through Softaculous? And what storage or data directory path is the installer, or the config.php it wrote, currently set to? If that path isn’t inside htdocs, that would explain the warning.