Hello,
I have a model like this:
class Entity(models.Model):    
    entity_name = models.CharField(max_length=100)
    entity_id = models.CharField(max_length=30, primary_key=True)
    entity_parent = models.CharField(max_length=100, null=True)
    photo_id = models.CharField(max_length=100, null=True)
    username = models.CharField(max_length=100, null=True)
    date_matched_on = models.CharField(max_length=100, null=True)
    status = models.CharField(max_length=30, default="Checked In")
    def __unicode__(self):
        return self.entity_name
    class Meta:
        app_label = 'match'
        ordering = ('entity_name','date_matched_on')
        verbose_name_plural='Entities'
I also have a view like this:
def photo_match(request):
''' performs an update in the db when a user chooses a photo '''
    form = EntityForm(request.POST)
    form.save()
And my EntityForm looks like this:
class EntityForm(ModelForm):
    class Meta:
        model = Entity
My template's form returns a POST back to the view with the following values:
 {u'username': [u'admin'], u'entity_parent': [u'PERSON'], u'entity_id': [u'152097'], u'photo_id': [u'2200734'], u'entity_name': [u'A.J. McLean'], u'status': [u'Checked Out'], u'date_matched_on': [u'5/20/2010 10:57 AM']}
And form.save() throws this error: 
  Exception in photo_match: The Entity could not be changed because the data didn't validate.
I have been trying to figure out why this is happening, but cannot pinpoint the exact problem.  I can change my Entities in the admin interface just fine.  If anybody has a clue about this I would greatly appreciate it!
Thanks,
Igor