>I have another question from a different directive which is producing an error now.
>
>This line
>
>datetimepicker.data("DateTimePicker").setDate...
>
>says: TypeError: Cannot read property 'setDate' of undefined
>
>and I can see that datetimepicker.data("DateTimePicker") returns undefined although datetimepicker is initialized and has data method.
>
>So, what is this new error about and what can I do now?

If this is related to the previous post then there're several bootstrap-datetimepicker.min.js variations
( https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=bootstrap-datetimepicker%20github )
Which one are you using (and are you sure you have inadvertently changed to a different version) ?