Can't move my attribute points anymore...

I was moving my attribute points arround trying different settings, and when I placed them all, my numbers grayed out and I can no longer move them..
Anyone know why this happened, bug maybe ?
Dr Wu.

Looks like you've spent all your attribute refund points.

And if that's the case you'll need to go fight some monsters to earn them back. 250 xp will get you one refund point.