WP plugins not updating - unable to remove

[Ezpro9]

how can i update plugins if i get this:

Downloading update from http://downloads.wordpress.org/plugin/akismet.2.5.7.zip…

Unpacking the update…

Installing the latest version…

Removing the old version of the plugin…

Could not remove the old plugin.

Plugin update failed.

same for AIOSEO

[ThompsonPaul]

You'll need to go in to your site on the server via ftp and remove the old version of the plugin manually before updating, Erik.

This error is often caused by misconfiguration of the permissions on the plugin folders on the server.

Paul