I inherited form the django user model like so:

from django.db import models
from django.contrib.auth.models import User, UserManager
from django.utils.translation import ugettext_lazy as _

class NewUserModel(User):
    custom_field_1 = models.CharField(_('custom field 1'), max_length=250, null=True, blank=True)
    custom_field_2 = models.CharField(_('custom field 2'), max_length=250, null=True, blank=True)

    objects = UserManager()

When i go to the admin and add an entry into this model, it saves fine, but below the "Password" field where it has this text "Use '[algo]$[salt]$[hexdigest]' or use the change password form.", if i click on the "change password form' link, it produces this error

Truncated incorrect DOUBLE value: '7/password'

What can i do to fix this?