Unfortunately whilst trying to install SS3 on shared hosting I'm getting the "Is the temporary directory writeable?" error.

I know this is a frequently asked question and that it should be an easy error to fix, but the solutions posted in these forums haven't worked in my case. I've tried creating 'silverstripe-cache' with 777 permissions in the following places:
/
/tmp/
/public_html/ (where cms, framework, etc. is located)

I'm struggling to understand why SS3 isn't finding this folder after realising that it doesn't have sufficient permissions to write to it on shared hosting. I've even tried changing the getTempFolder method in framework/core/Core.php.

I've had a lengthy conversation with technical support at Zen Hosting and the only solution they could come up with is to enquire on these forums.

Thanks in advance.

Hi Van, thanks for your reply.

Yes I'm in a Linux environment. How do I go about changing the ownership of a file? ftp doesn't have chown and I'm not sure how to ssh into the server. I've tried ssh c8690834@myzen.co.uk and ssh c8690834.myzen.co.uk. Furthermore, the control panel they have installed (cPanel) doesn't provide an equivalent functionality. Thanks again.