Debugging Java Webstart: System Process is opening tons of ports

I'm trying to debug a Java Webstart application which is causing the System Process with pid 0 to open thousands of tcp ports between 1000 and ~4000. The remote host is always localhost port 80, on which an Apache webserver is listening. The state of all connections is TIME_WAIT and there is no traffic at all.

After two days I have still no idea what's causing this behaviour since the application is running fine without using Java Webstart.

This is my JNLP file generated by Netbeans:

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<jnlp codebase="http://localhost:80/cwticket/" href="launch.jnlp" spec="1.0+">
<information>
    <title>CWTicket</title>
    <vendor>tstegman</vendor>
    <homepage href=""/>
    <description>CWTicket</description>
    <description kind="short">CWTicket</description>

</information>
<update check="background"/>
<security>
  <all-permissions/>
</security>
<resources>
<j2se version="1.5+"/>
<jar href="CWTicket.jar" main="true"/>
<jar href="lib/antlr-2.7.6.jar"/>
<jar href="lib/asm.jar"/>
<jar href="lib/asm-attrs.jar"/>
<jar href="lib/cglib-2.1.3.jar"/>
<jar href="lib/commons-collections-2.1.1.jar"/>
<jar href="lib/commons-logging-1.1.jar"/>
<jar href="lib/dom4j-1.6.1.jar"/&g开发者_开发知识库t;
<jar href="lib/ehcache-1.2.3.jar"/>
<jar href="lib/jdbc2_0-stdext.jar"/>
<jar href="lib/jta.jar"/>
<jar href="lib/hibernate3.jar"/>
<jar href="lib/hibernate-tools.jar"/>
<jar href="lib/hibernate-annotations.jar"/>
<jar href="lib/hibernate-commons-annotations.jar"/>
<jar href="lib/hibernate-entitymanager.jar"/>
<jar href="lib/javassist.jar"/>
<jar href="lib/ejb3-persistence.jar"/>
<jar href="lib/mysql-connector-java-5.1.6-bin.jar"/>
<jar href="lib/log4j.jar"/>
<jar href="lib/args4j-2.0.1.jar"/>
<jar href="lib/commons-lang-2.5.jar"/>
</resources>

<application-desc main-class="de.cw.cwticket.gui.TicketExplorerFrame">

</application-desc>
</jnlp>

Thank you very much for any hints!

Edit: The operating system is Windows XP SP3.