I Paid for JoomSEF3 couldn't get it to upgrade so I uninstalled it but now can't re-install. I keep getting below error?

JFolder::files: Path does not point to a valid folder or the folder has been deleted.
JFolder::folder: Path does not point to a valid folder or the folder has been deleted.
JFolder::files: Path does not point to a valid folder or the folder has been deleted.
Error! Could not find a Joomla! XML setup file in the package.

Hi,
Are you able to install any other component? It seems like some problem with your server's configuration. Check your directory permissions in Joomla's Help -> System Info menu.

Many thanks... I checked it doesn't have /libraries/joomla/installer/adapters showing in list, do I need to update this or can I update the php?

I'm sorry, I don't understand what exactly you mean by updating the php?
JoomSEF requires the /libraries/joomla/installer/adapters directory to be writable for the JoomSEF extensions installer to be working correctly. The directory is not writable by default, which may cause problems.

soo sorry to everyone who answered here, I had a very blonde moment.... I thought I had FTP layer off, just checked now and it was on... all installed nicely now. Thankyou for your help