update dashboard

when I try to install update to 3.2.4 this is what I get.
Installing the plugin…

Destination folder already exists. /hermes/bosweb/web061/b617/ipg.plunkslistcom/wp-content/plugins/wpmudev-updates/

Plugin install failed.

but I'm still getting the nag screen to update and I'm still showing the earlier version 3.2.3 in use. What I'm I missing? Thanks