Adding an individual to a single parent
PHPgedview does not let you add children to single individuals. You either have to create an imaginary husband or use the workaround below;
You add children to families and you create families by adding a spouse.
So, to create a single parent family, go to the individual you want to add a child to and select quick edit
1) create a "temporary" husband/wife
2) add the child to the new family
3) delete the temporary husband/wife
There is already a feature-request to be able to add the child directly, but since there is an easy workaround, it isn't high-priority.