I personally have never encountered this problem (I too have a powerbook w/10.3 and MySQL on it). My best guess is that the mysql-client libraries are either not installed, or that DBD::mysql cannot find them.

Try adding the mysql /bin directory to your path, this might fix the problem. I know in my MySQL installation the path is:

/Library/MySQL/bin

But that might not be the same for you, all depends upon how you installed MySQL.

-stvn