Проект, который запускался без проблем выдает следующее при запуске теперь:
log!ENTRY org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Bundle initial@reference:file:plugins/com.swtdesigner_4.2.1/ [15] was not resolved.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing required bundle org.eclipse.core.resources_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing required bundle org.eclipse.jdt.core_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing required bundle org.eclipse.jdt.ui_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing required bundle org.eclipse.jdt.launching_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing required bundle org.eclipse.jdt.debug.ui_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing required bundle org.eclipse.debug.ui_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.pde.core_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.pde.ui_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.search_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.ui.editors_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.ui.ide_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.ui.forms_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.ui.console_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.team.ui_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.text_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.jface.text_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.update.configurator_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.ltk.core.refactoring_0.0.0.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.99
!MESSAGE Missing optionally required bundle org.eclipse.ltk.ui.refactoring_0.0.0.

!ENTRY org.eclipse.osgi 2006-11-29 08:30:03.115
!MESSAGE Bundle initial@reference:file:../EclipseWorkspace/ru.nameapp/ [17] was not resolved.
!SUBENTRY 1 org.eclipse.osgi 2006-11-29 08:30:03.115
!MESSAGE Missing required bundle com.swtdesigner_0.0.0.

!ENTRY org.eclipse.osgi 2006-11-29 08:30:03.115
!MESSAGE Application error
!STACK 1
java.lang.RuntimeException: Application "ru.nameapp.application" could not be found in the registry. The applications available are: <NONE>.
at org.eclipse.core.internal.runtime.PlatformActivator$1.run(PlatformActivator.java:216)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:376)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:163)
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:585)
at org.eclipse.core.launcher.Main.invokeFramework(Main.java:334)
at org.eclipse.core.launcher.Main.basicRun(Main.java:278)
at org.eclipse.core.launcher.Main.run(Main.java:973)
at org.eclipse.core.launcher.Main.main(Main.java:948)


Подскажите, что я мог сделать не так?

Что хотел сделать - запустить проект.
Что делал до этого - поправил код в паре классов.
Что смутило - для меня эта ошибка абсолютно не понятна.
Результат - исправил путем очистки списка плагинов в конфигурации запуска, и заново прописал необходимые.
В общем методом научного тыка.