Load control template file /_controltemplates/TaxonomyPicker.ascx failed: Could not load type 'Microsoft.SharePoint.Portal.WebControls.TaxonomyPicker' from assembly

Ir a:

C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\CONTROLTEMPLATES

Abrir con notepad  TaxonomyPicker.ascx

Buscar "#44;" y remplazar por ","   y guardar.

Listo  :D