New to Java

How do I display a dialog with an indeterminate progress bar while a DB2 query runs? Could anyone point me to an example or some strong docs?

I learned Java about six months ago, so I'm relatively new to the language. Through searching and documentation, I've been able to find all the examples and answers I've needed so far. Now I've run into an issue I can't find anywhere. It seems like the most basic thing in the world. I have a DB2 stored procedure that takes about 5 minutes to run. While it's running, I want to display a simple dialog with a progress bar going back and forth (no buttons, no user interaction).

I'm using Eclipse 3.3.1.1 as my IDE, and running the application from a JAR file. I have Java 1.6.0.30 installed. The DB2 query is running in response to a user clicking a button on the form (an ActionEvent). All of my forms are using Swing (JFrame, JDialog, etc.).

The crux of my problem seems to be that I can bring up a dialog (which should contain the progress bar), but I can't get it to paint. All I get is a window that's the right size/location, but contains an after-image of what was behind it. I can't even get a dialog to display with a "Please Wait" label while the DB2 procedure runs.

I tried separating both the DB2 stored procedure and the progress dialog into separate threads. I tried yielding in the DB2 thread to give the progress dialog a chance to update. I tried using invokeAndWait, but I got the following error:
Exception in thread "AWT-EventQueue-0" java.lang.Error: Cannot call invokeAndWait from the event dispatcher thread

It seems like I'm doing something wrong in my use of Theads, but I can't for the life of me figure out what it is. If anyone could help out a bit of a Java newbie, I would be extremely grateful.