This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
There seems to be a case sensitivity issue.
If you have created your table with a lowercase name (e.g. by using create table "customer" in stead of create table customer), then your sql statement becomes case sensitive, and you will have to provide the query with the table name in the correct case, surrounded by quotes.