Unable to compile: Conversion to Dalvik format failed with error 1

What steps will reproduce the problem?
1. Using Eclipse + Android SDK & ADT + JDK 7u2
2. download the android vnc viewer package
3. install sqlitegen_eclipse_site-0.118 addon and try to compile the code, 
compilation failed

What is the expected output? What do you see instead?
[2012-01-15 22:19:07 - androidVNC] Dx 
UNEXPECTED TOP-LEVEL EXCEPTION:
java.lang.IllegalArgumentException: already added: 
Lcom/antlersoft/android/zoomer/ZoomControls;
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.dex.file.ClassDefsSection.add(ClassDefsSection.java:123)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.dex.file.DexFile.add(DexFile.java:163)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.command.dexer.Main.processClass(Main.java:486)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.command.dexer.Main.processFileBytes(Main.java:455)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.command.dexer.Main.access$400(Main.java:67)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.command.dexer.Main$1.processFileBytes(Main.java:394)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.cf.direct.ClassPathOpener.processArchive(ClassPathOpener.java:245
)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:131)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:109)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.command.dexer.Main.processOne(Main.java:418)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.command.dexer.Main.processAllFiles(Main.java:329)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.dx.command.dexer.Main.run(Main.java:206)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
java.lang.reflect.Method.invoke(Unknown Source)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.ide.eclipse.adt.internal.build.DexWrapper.run(DexWrapper.java:179)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.ide.eclipse.adt.internal.build.BuildHelper.executeDx(BuildHelper.jav
a:745)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.ide.eclipse.adt.internal.build.builders.PostCompilerBuilder.build(Po
stCompilerBuilder.java:634)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:728)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:199)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:321)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:396)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.resources.Project$1.run(Project.java:618)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.resources.Workspace.run(Workspace.java:2344)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.resources.Project.internalBuild(Project.java:597)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.resources.Project.build(Project.java:124)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.ide.eclipse.adt.internal.project.ProjectHelper.doFullIncrementalDebu
gBuild(ProjectHelper.java:961)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
com.android.ide.eclipse.adt.internal.launch.LaunchConfigDelegate.launch(LaunchCo
nfigDelegate.java:146)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.j
ava:854)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.debug.internal.core.LaunchConfiguration.launch(LaunchConfiguration.j
ava:703)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.debug.internal.ui.DebugUIPlugin.buildAndLaunch(DebugUIPlugin.java:92
8)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.debug.internal.ui.DebugUIPlugin$8.run(DebugUIPlugin.java:1132)
[2012-01-15 22:19:07 - androidVNC] Dx   at 
org.eclipse.core.internal.jobs.Worker.run(Worker.java:54)
[2012-01-15 22:19:07 - androidVNC] Dx 1 error; aborting
[2012-01-15 22:19:07 - androidVNC] Conversion to Dalvik format failed with 
error 1

What version of android-vnc-viewer are you using?
Build 203 - 20110327

Which VNC server/version are you using?  On which platform?
UltraVNC on win7-64

What is the size of the desktop you are trying to access?
1920 * 1200

What device are you using?
Android Emulator api 9

Are you using a custom ROM?
no

Please provide any additional information below.
I'm sure i have done almost every step on page, but when i though every all set,
it just shows up the "Conversion to Dalvik format failed with error 1" .
Project cleaning clicked but nothing changed.
Original issue reported on code.google.com by sin...@gmail.com on 15 Jan 2012 at 2:29
GDXN / android-vnc-viewer

Unable to compile: Conversion to Dalvik format failed with error 1 #287
