Index: wp-admin/includes/file.php
===================================================================
--- wp-admin/includes/file.php	(revision 7810)
+++ wp-admin/includes/file.php	(working copy)
@@ -259,13 +259,13 @@
 			$tmppath .= $path[$j] . '/';
 			if ( ! $fs->is_dir($to . $tmppath) )
 				if ( !$fs->mkdir($to . $tmppath, 0755) )
-					return new WP_Error('mkdir_failed', __('Could not create directory'));
+					return new WP_Error('mkdir_failed', __("Could not create directory: $to$tmppath"));
 		}
 
 		// We've made sure the folders are there, so let's extract the file now:
 		if ( ! $file['folder'] )
 			if ( !$fs->put_contents( $to . $file['filename'], $file['content']) )
-				return new WP_Error('copy_failed', __('Could not copy file'));
+				return new WP_Error('copy_failed', __("Could not copy file to $to"));
 			$fs->chmod($to . $file['filename'], 0644);
 	}