Java GUI will not launch in linux

[jameskozlowski]

javax.swing.plaf.metal.MetalLookAndFeel
-- listing properties --
java.runtime.name=OpenJDK Runtime Environment
sun.boot.library.path=/usr/lib/jvm/java-7-openjdk-amd64/jre...
java.vm.version=23.7-b01
java.vm.vendor=Oracle Corporation
java.vendor.url=http://java.oracle.com/
path.separator=:
java.vm.name=OpenJDK 64-Bit Server VM
file.encoding.pkg=sun.io
user.country=CA
sun.java.launcher=SUN_STANDARD
sun.os.patch.level=unknown
java.vm.specification.name=Java Virtual Machine Specification
user.dir=/home/jkozlowski/Desktop/Papilio-Load...
java.runtime.version=1.7.0_21-b02
java.awt.graphicsenv=sun.awt.X11GraphicsEnvironment
java.endorsed.dirs=/usr/lib/jvm/java-7-openjdk-amd64/jre...
os.arch=amd64
java.io.tmpdir=/tmp
line.separator=

java.vm.specification.vendor=Oracle Corporation
os.name=Linux
sun.jnu.encoding=UTF-8
java.library.path=/usr/java/packages/lib/amd64:/usr/lib...
sun.awt.enableExtraMouseButtons=true
java.specification.name=Java Platform API Specification
java.class.version=51.0
sun.management.compiler=HotSpot 64-Bit Tiered Compilers
os.version=3.8.0-19-generic
user.home=/root
user.timezone=
java.awt.printerjob=sun.print.PSPrinterJob
file.encoding=UTF-8
java.specification.version=1.7
user.name=root
java.class.path=bin
java.vm.specification.version=1.7
sun.arch.data.model=64
java.home=/usr/lib/jvm/java-7-openjdk-amd64/jre
sun.java.command=net.gadgetfactory.papilio.loader.Papi...
java.specification.vendor=Oracle Corporation
user.language=en
awt.toolkit=sun.awt.X11.XToolkit
java.vm.info=mixed mode
java.version=1.7.0_21
java.ext.dirs=/usr/lib/jvm/java-7-openjdk-amd64/jre...
sun.boot.class.path=/usr/lib/jvm/java-7-openjdk-amd64/jre...
java.vendor=Oracle Corporation
file.separator=/
java.vendor.url.bug=http://bugreport.sun.com/bugreport/
sun.cpu.endian=little
sun.io.unicode.encoding=UnicodeLittle
sun.font.fontmanager=sun.awt.X11FontManager
sun.cpu.isalist=
Exception in thread "AWT-EventQueue-0" java.lang.ClassFormatError: Illegal UTF8 string in constant pool in class file net/gadgetfactory/papilio/loader/HelperFunctions
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:787)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:447)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
at net.gadgetfactory.papilio.loader.TargetPanel.(TargetPanel.java:232)
at net.gadgetfactory.papilio.loader.PapilioLoader.(PapilioLoader.java:251)
at net.gadgetfactory.papilio.loader.PapilioLoader$1.run(PapilioLoader.java:178)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:727)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:688)
at java.awt.EventQueue$3.run(EventQueue.java:686)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:697)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)