- import import QtMobility.contacts 1.1 instead of 1.2 as documented
in the QtContacts 1.2 API
- main.qml and ContactsPage.qml used DetailFilter to check ContactDetail.PhoneNumber without specifying the value where to compare. This filtered all contacts away.
Fix is simply to remove the DetailFilter from the main.qml and ContactPage.qml.

Alternative would be to show only contacts having at least 1 phonenumber. That could be
done with a following DetailRangeFilter:
filter: DetailRangeFilter {
detail: ContactDetail.PhoneNumber
field: PhoneNumber.SubTypes
min: 1
}

I anyway think it's better to show even those contacts which does not have phone number.