JNLP ParseException - Only one application descriptor element allowed per JNLPFile

[ch3]

When I start jnlp aplication I get that error:

net.sourceforge.jnlp.LaunchException: Fatal: Read Error: Could not read or parse the JNLP file.
 at net.sourceforge.jnlp.Launcher.fromUrl(Launcher.java:491)
 at net.sourceforge.jnlp.Launcher.launch(Launcher.java:283)
 at net.sourceforge.jnlp.runtime.Boot.run(Boot.java:199)
 at net.sourceforge.jnlp.runtime.Boot.run(Boot.java:51)
 at java.security.AccessController.doPrivileged(Native Method)
 at net.sourceforge.jnlp.runtime.Boot.main(Boot.java:165)
Caused by: net.sourceforge.jnlp.ParseException: Only one application descriptor element allowed per JNLPFile.
 at net.sourceforge.jnlp.Parser.getLauncher(Parser.java:589)
 at net.sourceforge.jnlp.JNLPFile.parse(JNLPFile.java:592)
 at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:178)
 at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:162)
 at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:148)
 at net.sourceforge.jnlp.Launcher.fromUrl(Launcher.java:477)
 ... 5 more
Caused by:
net.sourceforge.jnlp.ParseException: Only one application descriptor element allowed per JNLPFile.
 at net.sourceforge.jnlp.Parser.getLauncher(Parser.java:589)
 at net.sourceforge.jnlp.JNLPFile.parse(JNLPFile.java:592)
 at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:178)
 at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:162)
 at net.sourceforge.jnlp.JNLPFile.<init>(JNLPFile.java:148)
 at net.sourceforge.jnlp.Launcher.fromUrl(Launcher.java:477)
 at net.sourceforge.jnlp.Launcher.launch(Launcher.java:283)
 at net.sourceforge.jnlp.runtime.Boot.run(Boot.java:199)
 at net.sourceforge.jnlp.runtime.Boot.run(Boot.java:51)
 at java.security.AccessController.doPrivileged(Native Method)
 at net.sourceforge.jnlp.runtime.Boot.main(Boot.java:165)

This happens every time - no mater if I use command line or IcedTea plugin
for example by running one of that commands:

# /usr/lib/jvm/java-6-openjdk/bin/javaws http://www.xtb.pl/repository/Downloads/sidoma_kl.jnlp
# javaws http://www.xtb.pl/repository/Downloads/sidoma_kl.jnlp
# javaws http://193.193.181.210/sidoma8/sidoma8ingskl/sidoma.jnlp
# javaws https://ssl.idmsa.pl/sidoma8/sidoma_kl.jnlp

Other jnlp apps run just fine f.e.
# javaws http://download.oracle.com/javase/tutorialJWS/uiswing/misc/ex6/TextAreaPrintingDemo.jnlp

my current java and system:
# lsb_release -rd
Description: Ubuntu 11.04
Release: 11.04
# java -version
java version "1.6.0_22"
OpenJDK Runtime Environment (IcedTea6 1.10.4) (6b22-1.10.4-0ubuntu1~11.04.2)
OpenJDK 64-Bit Server VM (build 20.0-b11, mixed mode)

This could be related to:
https://bugs.launchpad.net/ubuntu/+source/openjdk-6/+bug/781819
https://bugs.launchpad.net/ubuntu/+source/openjdk-6/+bug/905961
but error is not the same, so I decided to fill another bug.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.