error by selecting afx file

eclipse.buildId=M20100909-0800
java.version=1.6.0_22
java.vendor=Sun Microsystems Inc.
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=it_IT
Framework arguments: -product org.eclipse.epp.package.jee.product
in backtrace view
Command-line arguments: -os linux -ws gtk -arch x86_64 -product org.eclipse.epp.package.jee.product

java.lang.NoSuchMethodError: org.apache.commons.lang.StringUtils.endsWithIgnoreCase(Ljava/lang/String;Ljava/lang/String;)Z
at com.swi.tm.ui.commons.dialog.ChooseFileDialog.(ChooseFileDialog.java:63)
at com.swi.tm.ui.commons.dialog.ChooseFileDialog.openDialog(ChooseFileDialog.java:270)
at com.swi.tm.ui.commons.dialog.ChooseFileDialog.openDialog(ChooseFileDialog.java:265)
at com.swi.tm.ui.commons.dialog.ChooseFileDialog.openDialog(ChooseFileDialog.java:259)
at com.swi.tm.ui.backtraces.BacktracesPage.openAxfFileDialog(BacktracesPage.java:217)
at com.swi.tm.ui.backtraces.BacktracesPage.access$3(BacktracesPage.java:216)
at com.swi.tm.ui.backtraces.BacktracesPage$5.widgetSelected(BacktracesPage.java:241)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:234)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1258)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3540)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3161)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2640)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:671)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:619)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574)
at org.eclipse.equinox.launcher.Main.run(Main.java:1407)
at org.eclipse.equinox.launcher.Main.main(Main.java:1383)

Ok, point logged
Probably due to a wrong version of org.apache.common.lang in your Eclipse.
Please can you have a look to this plug-in version in your installation?

really surprised!
I have two version of this library: 2.1.0 and 2.3.0. How is possible? The plugin id seems to be the same…

And DS needs 2.4.0…
Even if several jar files are present, only the latest one will be enabled.
Next DS release will fix the issue with a strong requirement on 2.4.0 release (current one isn’t strong enough and is satisfied if any version is already installed)