class UserProfileForm(forms.ModelForm):
    first_name = forms.CharField(max_length=30)
    last_name = forms.CharField(max_length=30)

    class Meta:
        model = UserProfile
        fields = ('deposited_money',)

    def __init__(self, user, *args, **kwargs):
        super(UserProfileForm, self).__init__(*args, **kwargs)
        self.fields['first_name'].initial = user.first_name
        self.fields['last_name'].initial = user.last_name

    def save(self, commit=True):
        profile = super(UserProfileForm, self).save(commit=commit)
        user = profile.user
        user.first_name = self.cleaned_data["first_name"]
        user.last_name = self.cleaned_data["last_name"]
        if commit:
            user.save(commit=commit)
        return profile

#### creo el form en la vista:
user_form = UserProfileForm(request.user, instance=request.user.get_profile())

#### creo el form basado en el POST:
form = UserProfileForm(request.POST, instance=request.user.get_profile())

### Y al hacer el submit me sale error en el __init__:
        'QueryDict' object has no attribute 'first_name'