drupal : content type CCK - add an existing field disappeared?

I recently installed a drupal from scratch and I'm installing additional modules according to my needs.

The biggest problem I have is that if I go in

admin/content/node-type/NODETYPENAME/fields

(the page where I can edit/add/delete the CCK fields) I can't re-use defined fields the Option Add existing fields simply disappeared (probably it's some module that I don't know about) I have only New Field and New group ..in my other installation I have the Existing Field option where I can reuse already defined fields...

AM I missing something?

my CCK module page looks like this:

CCK
Activado    Nombre  Versión Descripción

Content 6.x-2.8 Permitir a los administradores definir nuevos tipos de contenidos.
Requerido por: Content Copy (desactivado), Content Permissions (activado), Content Taxonomy (activado), Content Taxonomy Autocomplete (activado), Content Taxonomy Options (activado), Content Taxonomy Tree (desactivado), Date (activado), Date Tools (desactivado), Email (activado), Fieldgroup (activado), FileField (activado), CCK translation (activado), ImageField (activado), Node Reference (activado), Number (activado), Option Widgets (activado), Text (activado), Video Upload (activado), User Reference (desactivado), Video (activado), Vi开发者_如何学编程deo FTP (desactivado), FileField Meta (desactivado), Amazon S3 on Video (desactivado), Zencoder API on Video (desactivado)

Content Copy    6.x-2.8 Enables ability to import/export field definitions.
Depende de: Content (activado)

Content Permissions 6.x-2.8 Set field-level permissions for CCK fields.
Depende de: Content (activado)

Content Taxonomy    6.x-1.0-rc2 Defines a field type for taxonomy terms
Depende de: Content (activado), Taxonomy (activado)
Requerido por: Content Taxonomy Autocomplete (activado), Content Taxonomy Options (activado), Content Taxonomy Tree (desactivado)

Content Taxonomy Autocomplete   6.x-1.0-rc2 Defines a autocomplete widget type for content_taxonomy
Depende de: Content (activado), Content Taxonomy (activado), Taxonomy (activado)

Content Taxonomy Options    6.x-1.0-rc2 Defines a option widget type for content_taxonomy for selects, radios/checkboxes
Depende de: Content (activado), Content Taxonomy (activado), Taxonomy (activado), Option Widgets (activado)

Content Taxonomy Tree   6.x-1.0-rc2 Defines a dynamic tree widget for Content Taxonomy
Depende de: Content (activado), Content Taxonomy (activado), Taxonomy (activado), Taxonomy_manager (desaparecido)

Email   6.x-1.2 Defines an email field type for cck
Depende de: Content (activado)

Fieldgroup  6.x-2.8 Create display groups for CCK fields.
Depende de: Content (activado)

FileField   6.x-3.7 Defines a file field type.
Depende de: Content (activado)
Requerido por: FileField Meta (desactivado), ImageField (activado), Video Upload (activado), Video (activado), Video FTP (desactivado), Amazon S3 on Video (desactivado), Zencoder API on Video (desactivado)

FileField Meta  6.x-3.7 Add metadata gathering and storage to FileField.
Depende de: FileField (activado), Getid3 (desaparecido), Content (activado)

ImageField  6.x-3.7 Define un campo de tipo imagen
Depende de: Content (activado), FileField (activado)

Node Reference  6.x-2.8 Defines a field type for referencing one node from another.
Depende de: Content (activado), Text (activado), Option Widgets (activado)

Number  6.x-2.8 Defines numeric field types.
Depende de: Content (activado)

Option Widgets  6.x-2.8 Defines selection, check box and radio button widgets for text and numeric fields.
Depende de: Content (activado)
Requerido por: Content Taxonomy Options (activado), Node Reference (activado), User Reference (desactivado)

Text    6.x-2.8 Defines simple text field types.
Depende de: Content (activado)
Requerido por: Node Reference (activado), User Reference (desactivado)

User Reference  6.x-2.8 Defines a field type for referencing a user from a node.
Depende de: Content (activado), Text (activado), Option Widgets (activado)

Ok, here was the answer, Using existing fields doesn't appear ONLY when you have multiple content types defined and custom CCK fields attached to it