Why won't my BlackBerry Playbook charge anymore when I plug it in to the 110v socket?

My blackberry playbook won't charge any more when I plug it in. The red light goes on when I press it for a few seconds followed by a yellow light which blinks five times and then goes dead. I think it is the chord, am I right? It wouldn't charge overnight.
Les Sharples
Etobicoke

I would definitely try another power plug before moving to another solution. I've had messed-up cable make me think I had a charging issue before. It's as good a place as any to start.