"I just intalled cdrecord and try to write on a cdrw and great, it works. But then I tried to rewrite on the same cdrw and it didn't worked. I tried to blank the cdrw with fast and then all but it doesn't worked either. It sees my cdrw as a complete cdr."
One of the things that might cause this problem is when you have a mismatch between the rated speeds of the cd-rw CD and the cd-rw drive.
Be prepared. Create a LifeBoat CD.