How can I disable cck button in node edit ?

I inserted code in hook_form_alter:

if($form_id == 'page_node_form') {
		
		$form[field_gmap_button] = array(
		    '#type' => 'hidden'		    
		);
		
	}

and remove button in node edit but in node view too and get error

warning: Invalid argument supplied for foreach() in C:\www\...sites\all\modules\cck\content.module on line 450.

print_r($form)

[field_gmap_button] => Array
        (
            [#tree] => 1
            [#weight] => 0
            [#type] => fieldset
            [#title] => Mubutton
            [#description] => 
            [0] => Array
                (
                    [button_enabled] => Array
                        (
                            [#type] => checkbox
                            [#title] => Enable button
                            [#default_value] => 1
                        )

                    [button_label] => Array
                        (
                            [#type] => hidden
                            [#value] => Submit
                        )

                    [button_html] => Array
                        (
                            [#type] => hidden
                            [#value] => type="button" class="cck-button"

                        )

                    [button_php] => Array
                        (
                            [#type] => hidden
                            [#value] => // Sample code (show how to handle a click event with jQuery):
drupal_add_js( 
      '$(document).ready(function() {  
            $("input.cck-button").toggle(function() { 
                  $label = $(this).val();
                  $(this).val("Click me!");
            }, function() {
                  $(this).val($label).fadeIn("slow");
            } );
       } ); ',
       'inline'
);

                        )

                )

        )