I'm not sure the exact problem. Did it show you what line of code caused the error?
I would suggest starting over and just putting this at the bottom of db.py
(starting at about line 80). This worked OK for me.
db.define_table('estudantes',
Field('nome'),
Field('pais'),
Field('nascimento', 'date'),
Field('sexo'),
Field('email'))
Some tips: 1) try to avoid changing or deleting what web2py gives you, 2)
use all lower case names and 3) don't rename things unnecessarily.
