Having been developing my PL/SQL in Toad Data Modeler, and running via a customer VB program, the debugging effort has been poor at best. A co-worker pointed me to Oracle SQL Developer, it’s in the league as MS SQL Server Management Studio, but for Oracle!
The other point I’ve been tripping on, in PL/SQL to use a date (via SQL*Plus) to_date('2007-08-06','YYYY-MM-DD') is the trick.