Problem with adding Views - they cannot be saved I have problem with creating new views (or clone old ones). All process is doing well, I choose my filtres etc; but when I'm trying to save it's an error - and they don't show in the views list (even if it's said that it "has been saved"). I've already tried several times but it doesn't work. I dont know why - before I didn't have this problem...
Have you tried running update.php? Or try clearing the Drupal cache which you can do quickly with drush using drush cc all.

I find this is always a good place to start.