Session_save_path not writable

I'm testing an e-commerce script for a paid project on one of my test sites, but I get this error

Quote:

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If you can not login or products are not stored in the shopping cart or get errors in the log like 'session_start failed', 'Failed to write session data', 'save_path is not writable', 'Invalid token session. Please login again'. Session_save_path is a PHP variable that is set in php.ini, and on many shared hosting setups it’s actually set to a location that’s not writable.

Contact your host to solve this.

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You can see it on here: http://ninjatest4.altervista.org/static_pages/index.php

Can I have anyone making such thing to be writable please?
Thanks in advance.

Which CMS are you trying to use? Is it trying to write directly in session_save_path? Why?

http://www.abantecart.com/

I managed to install the CMS, but I don't get any error. What did you change in order to show that error message?

Nothing, I just installed it. It happens after you installed it, while trying to view it.

Which version did you install? Did you activate PHP 5.6 on your webspace?
I'm not able to reproduce the issue: I installed AbanteCart 1.2.8 without problems (PHP 5.6 was active).