Caught an exception while rendering: 'FieldFile' object has no attribute 'rfind'

Original Traceback (most recent call last):
  File "/home/adv/webapps/django/lib/python2.5/django/template/debug.py", line 71, in render_node
    result = node.render(context)
  File "/home/adv/webapps/django/lib/python2.5/django/template/debug.py", line 87, in render
    output = force_unicode(self.filter_expression.resolve(context))
  File "/home/adv/webapps/django/lib/python2.5/django/utils/encoding.py", line 71, in force_unicode
    s = unicode(s)
  File "/home/adv/webapps/django/lib/python2.5/django/forms/forms.py", line 356, in __unicode__
    return self.as_widget()
  File "/home/adv/webapps/django/lib/python2.5/django/forms/forms.py", line 391, in as_widget
    return widget.render(name, data, attrs=attrs)
  File "/home/adv/webapps/django/lib/python2.5/django/forms/widgets.py", line 653, in render
    output.append(widget.render(name + '_%s' % i, widget_value, final_attrs))
  File "/home/adv/webapps/django/adv/pages/removable_fields.py", line 26, in render
    s += u'<br><a href="%s%s">%s</a>' % (settings.MEDIA_URL, value, os.path.basename(value))
  File "/usr/local/lib/python2.5/posixpath.py", line 112, in basename
    return split(p)[1]
  File "/usr/local/lib/python2.5/posixpath.py", line 77, in split
    i = p.rfind('/') + 1
AttributeError: 'FieldFile' object has no attribute 'rfind'