It sounds like the battery drained completely.
There is not anything wrong with the charger. If I am correct with what I have already experienced, then changing the adapter will make no difference.
With the Blackberry Playbook, if you let the battery drain too far, then it is a pain to get it going. But it IS possible.
What you need to do is put the USB charger in the Playbook and remove it a few seconds later. You will need to repeat this over and over until the Playbook has enough charge to charge normally.
This procedure can take anywhere from 10 minutes to an hour.
PD