create JAR-file: works in Eclipse, not in NetBeans

I am running Eclipse 3.2 and NetBeans 5.5.1 and tried to create a JAR file of my project. This works fine in Eclipse - but not in Netbeans; when creating a JAR file in Netbeans I can start my application but the whole GUI isn't being displayed. I don't get an error message or another feedback.

I am working with the JDK 6 Update 1.

Where can I start troubleshooting?

[388 byte] By [SFLa] at [2007-11-27 10:02:40]
# 1
Eliminate IDEs from the equation. Write an Ant script to build and package your jar
georgemca at 2007-7-13 0:37:02 > top of Java-index,Desktop,Deploying...
# 2
Hmmm... but since these 2 IDEs do have the function to create JAR-files I would be glad to use them ;)Otherwise I am going to use the jar command line tool :/
SFLa at 2007-7-13 0:37:02 > top of Java-index,Desktop,Deploying...
# 3
Then you are involving your IDE in your build process, which isn't ideal. Learn to use Ant, it'll save you a massive amount of hassle and effort
georgemca at 2007-7-13 0:37:02 > top of Java-index,Desktop,Deploying...