Hi,
I just hit the same problem as the original question here.
My Tomcat server runs on a Linux box and I was connecting through a browser on Windows.
I found I got it to work by doing two things
1) Open port 3306 on the Linux box
http://www.instantsupportsite.com/self-help/ubuntu-mysql-port-3306/
2) I also set the permissions in MySQL
I leave this info here in the hope it helps someone, some day, some how!
Chris