very strange problem with editing/deleting nodes

Hi,

I have a very strange problem with editing and deleting some existing nodes in my drupal site.

To remove a node, if I click 'edit' button, I can only see the following message:
warning: call_user_func_array(): First argumented is expected to be a valid callback, 'fictive_art_node_form' was given in /home/fictive/includes/form.inc on line 218.

FYI, I have both 'path' module and clean URL enabled. All newly created contents works fine. Only few nodes with costom URL paths have this problem. (Most nodes with costum URL paths are also fine.)

The other problem related to this matter is following:
In my drupal site, I've removed a node with an alternative URL path called 'airplane_payne' last week, and I had to create a new node with the same name, 'airplane_payne' today. However, when I put 'airplane_payne' in the URL path blank in the new content creation, it shows 'The path is already in use.' That means I think the previous 'airplane_payne' node was not completely removed from my site for some reason. So I visited http://www.mydrupalsite.com/airplane_payne to see what the problem is, but it shows only blank page with a 'read more' link. So I clicked it, and it didn't go to the 'airplane_payne' page but to the front page.

Is there anyone can help me to solve this problem?
In advance, thank you for your time and help.