I just upgraded from 2.07 to 2.3.1 and am unable to edit any plugins from the Admin | Plugin Management page.
For example, if I click on the 'Edit' link of the Akismet plugin, I receive the following error message:
Sorry, can’t call files with their real path.
(The url that shows the error is:
http://blog.shareflo.com/wp-admin/plugin-editor.php?file=akismet/akismet.php)
My platform is Windows. All of the plug-in Edit links return this same error message. However, I am able to successfully activate plugins (no error message returned).