"Why can't you cook?"

Translation: Dlaczego nie umiecie gotować?

[AthanasGiew]

When there are two verb second one is infinitive

[immerweiter]

is this wrong? dlaczego nie może ugotować

[Michael.Lubetsky]

My understanding (and I stand to be corrected) is that "umie" means more "knows how to" while "moze" refers to physically being able to do something at a particular moment.

[Jellei]

Yup, sounds about right.