Trouble with connection in a certain case

Hello every one

We have a Java-Web-Start application, wich comunicates via soap to a Server written in Soap-RPC Services (Apache, Java)
usualy that works fine even with proxies, which can be configured in the application
In one certain case a customer got trouble not getting a connect at all, when the RPCs are used, although
the Web-Start gets contact to the same server downloading the Application successfully.
What could be the trouble? Does anybody has an idea and can give me a hint? it Seems to be a certain topology of the customers LAN I guess, but what could it be which makes the trouble?
Here is the exception

URL = http://62.159.207.333/soap/servlet/rpcrouter - Methode = connectToDB
[SOAPException: faultCode=SOAP-ENV:Client; msg=Error connecting to 62.159.207.333:80: java.net.ConnectException: Connection refused: connect; targetException=java.net.ConnectException: Connection refused: connect]
	at org.apache.soap.util.net.HTTPUtils.getSocket(Unknown Source)
	at org.apache.soap.util.net.HTTPUtils.post(Unknown Source)
	at org.apache.soap.util.net.HTTPUtils.post(Unknown Source)
	at org.apache.soap.transport.http.SOAPHTTPConnection.send(Unknown Source)
	at org.apache.soap.rpc.Call.invoke(Unknown Source)
	at org.apache.soap.rpc.Call.invoke(Unknown Source)
	at de.mc.etnbestterm.data.SoapCallingDataHolder.callSoaply(SoapCallingDataHolder.java:75)
	at de.mc.etnbestterm.data.MainDataHolder.connectServerToDB(MainDataHolder.java:457)
	at de.mc.etnbestterm.data.MainDataHolder.<init>(MainDataHolder.java:61)
	at de.mc.etnbestterm.data.SingletonManager.getMainDataHolder(SingletonManager.java:46)
	at de.mc.etnbestterm.gui.WillkommenPanel.jbInit(WillkommenPanel.java:62)
	at de.mc.etnbestterm.gui.WillkommenPanel.<init>(WillkommenPanel.java:52)
	at de.mc.etnbestterm.gui.MainFrame.<init>(MainFrame.java:40)
	at de.mc.etnbestterm.Bestellterminal.jbInit(Bestellterminal.java:64)
	at de.mc.etnbestterm.Bestellterminal.<init>(Bestellterminal.java:44)
	at de.mc.etnbestterm.Bestellterminal.main(Bestellterminal.java:117)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.sun.javaws.Launcher.executeApplication(Unknown Source)
	at com.sun.javaws.Launcher.executeMainClass(Unknown Source)
	at com.sun.javaws.Launcher.continueLaunch(Unknown Source)
	at com.sun.javaws.Launcher.handleApplicationDesc(Unknown Source)
	at com.sun.javaws.Launcher.handleLaunchFile(Unknown Source)
	at com.sun.javaws.Launcher.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.net.ConnectException: Connection refused: connect
	at java.net.PlainSocketImpl.socketConnect(Native Method)
	at java.net.PlainSocketImpl.doConnect(Unknown Source)
	at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
	at java.net.PlainSocketImpl.connect(Unknown Source)
	at java.net.Socket.connect(Unknown Source)
	at java.net.Socket.connect(Unknown Source)
	at java.net.Socket.<init>(Unknown Source)
	at java.net.Socket.<init>(Unknown Source)
	at org.apache.soap.util.net.SocketUtils.createSocket(Unknown Source)
	at org.apache.soap.util.net.HTTPUtils.getSocket(Unknown Source)
	at org.apache.soap.util.net.HTTPUtils.post(Unknown Source)
	at org.apache.soap.util.net.HTTPUtils.post(Unknown Source)
	at org.apache.soap.transport.http.SOAPHTTPConnection.send(Unknown Source)
	at org.apache.soap.rpc.Call.invoke(Unknown Source)
	at org.apache.soap.rpc.Call.invoke(Unknown Source)
	at de.mc.etnbestterm.data.SoapCallingDataHolder.callSoaply(SoapCallingDataHolder.java:75)
	at de.mc.etnbestterm.data.MainDataHolder.connectServerToDB(MainDataHolder.java:457)
	at de.mc.etnbestterm.data.MainDataHolder.<init>(MainDataHolder.java:61)
	at de.mc.etnbestterm.data.SingletonManager.getMainDataHolder(SingletonManager.java:46)
	at de.mc.etnbestterm.gui.WillkommenPanel.jbInit(WillkommenPanel.java:62)
	at de.mc.etnbestterm.gui.WillkommenPanel.<init>(WillkommenPanel.java:52)
	at de.mc.etnbestterm.gui.MainFrame.<init>(MainFrame.java:40)
	at de.mc.etnbestterm.Bestellterminal.jbInit(Bestellterminal.java:64)
	at de.mc.etnbestterm.Bestellterminal.<init>(Bestellterminal.java:44)
	at de.mc.etnbestterm.Bestellterminal.main(Bestellterminal.java:117)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.sun.javaws.Launcher.executeApplication(Unknown Source)
	at com.sun.javaws.Launcher.executeMainClass(Unknown Source)
	at com.sun.javaws.Launcher.continueLaunch(Unknown Source)
	at com.sun.javaws.Launcher.handleApplicationDesc(Unknown Source)
	at com.sun.javaws.Launcher.handleLaunchFile(Unknown Source)
	at com.sun.javaws.Launcher.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)