How to set the default value of a CCK field
In order for you to use PHP you must return a simpler array:

return array(
  'value' =&gt; 'my_text'
);


Also, if all you want is to set a default value, you don't need to use the PHP option.


First, define the allowed values (manually or via PHP, doesn't matter)
Then click save
Now click edit to go back to the form. Close to the top there will be a "Default Value" fieldset populated with the allowed values. Just select one!