If GECAMed doesn't react after you clicked the “apply rules” button in the billing module or tried to print something, your JBoss server is probably using the wrong Java version. This usually happens after you have applied one of Apples Java upgrade patches.
To correct that problem you have to make sure that your Mac OS is linking to the Java versions that is required for a GECAMed server (1.5). To do so proceed as described in Change the Java version used by the JBoss.
Afterwards make sure your JBoss is using this link. To change the Java version used by your JBoss you need to modify the “run.conf” file in the folder “«GECAMed»/jboss-4.0.5.GA/bin”. Normally the file is write protected by the root user and cannot be changed easily. To change it open the terminal, go to the bin folder and open the file in the “VI” using the command “sudo vi ./run.conf”. Add the line JAVA_HOME=“/System/Library/Frameworks/JavaVM.framework/Versions/1.5.0/Home” to the file and save it.
After you did that you need to restart your JBoss server.