You may have a problem on Ownership of your files.
The upload files can not not Be move files to the wp-content / ..
Downloading update from http://downloads.wordpress.org/plugin/. ..
Unpacking the update
Deactivating the plugin
Removing the old release of the plugin
Could not remove the old plugin
Failed upgrade Plugin
This is probably a permission problem.
With your device you can run the command:
/home/fixperm.sh user
user is the folder of your user on your WHM.