jdbc + postgres

Hello,

I have following program:

----------------------- CUT ------------------------
import java.net.URL;
import java.sql.*;

....

String url = "jdbc:postgresql://localhost/store3";
//String url = "jdbc:postgresql:store3";
Connection db;
Statement st;

TillInfo () {
try {
System.err.println ( "Loading driver ..." );
Class.forName ("postgresql.Driver");
} catch (java.lang.ClassNotFoundException e) {
System.err.print ("ClassNotFoundException:");
System.err.println (e.getMessage());
}

try {
System.err.println ( "Connecting ..." );
db = DriverManager.getConnection (url,"przemol","przemol");
System.err.println ( "Preparing statement ..." );
st = db.createStatement ();
System.err.println ( "Executing query ..." );
ResultSet rs = st.executeQuery (query);
if (rs != null) {
....
}
st.close ();
db.close ();
} catch (SQLException ex) {
System.err.println ( "SQLState:" + ex.getSQLState() );
System.err.println ( "Message:" + ex.getMessage() );
System.err.println ( "Vendor:" + ex.getErrorCode() );
}
}

------------------ CUT ------------------

While running I have message:

Loading driver ...
Connecting ...
SQLState:null
Message:Connection failed: java.net.ConnectException: Connection refused
Vendor:0
Exception occurred during event dispatching:
java.lang.ArithmeticException: / by zero
at PanelChart.paint(PanelChart.java:11)
at java.awt.Component.dispatchEventImpl(Component.java:1401)
at java.awt.Component.dispatchEvent(Component.java:1382)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:63)

Could you tell me whats wrong with my program ?
Do I have to change sources ? If so can you tell me how ?
I use jdbc driver from postgres 6.3.2 sources and jdk 1.1.3.
Of course postgres is running :))

przemol