Index: css_injector.install
===================================================================
--- css_injector.install	(revision 660)
+++ css_injector.install	(working copy)
@@ -49,7 +49,8 @@
         'description' => 'The path of the CSS file to inject',
         'type' => 'varchar',
         'length' => 255,
-        'not null' => TRUE),
+        'not null' => TRUE,
+        'default' => ''),
     ),
     'primary key' => array('crid'),
   );