This error show when upgrade via joomla installer.
-1 - An error has occurred.
Copy failed
Hello wat,
The error is because of your permission issue: http://screencast.com/t/PMmVebbBJa6c . Seems like most of the directory is unwritable. You have to make it writable to install. Hope this helps.
Did you just manually changed to 777? You need to check with your webhoster about this permission issue. Because I've tried to install other component still got error.