svn & akismet

Whenever I install a blog using svn Akismet cannot be updated via plug-in update system as I get the following message:

An error occured while updating Akismet: Could not remove the old plugin..

The only way to run the latest version of Akismet is to delete it and install manually. But then this becomes a problem each svn update.

Anyway to get this working so Akismet can be updated via the plug-in system between wordpress svn updates.