With the risk of sounding like a dork, the problem is that your temp directory is not writable. This is exactly what the error message tells you. Please note a common misconception here. Just the permissions alone do not a directory writeable make. It is the combination of both ownership and permissions which determines the writability of a directory. This is why the error message suggests that you either modify the permissions (fixing the permissions side of the equation) or enable FTP (fixing the ownership side of the equation). There is nothing else you can do. This is how the operating system works. I cannot do something against the way the operating system works. Neither does Joomla!.
Nicholas K. Dionysopoulos
Lead Developer and Director
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