Help!! RTC will not start

Hello. I just added some add-ons (for BIRT reporting). Once I was done, I was prompted to restart RTC. I did that, but RTC will not start and this is what I see in the log file. Can someone tell what I need to do to get RTC back again?

!SESSION Tue Sep 20 09:45:13 PDT 2011 ------------------------------------------
!ENTRY org.eclipse.equinox.launcher 4 0 2011-09-20 09:45:13.859
!MESSAGE Exception launching the Eclipse Platform:
!STACK
java.lang.ClassNotFoundException: org.eclipse.core.runtime.adaptor.EclipseStarter
at java.net.URLClassLoader.findClass(URLClassLoader.java:497)
at java.lang.ClassLoader.loadClass(ClassLoader.java:639)
at java.lang.ClassLoader.loadClass(ClassLoader.java:605)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:556)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:514)
at org.eclipse.equinox.launcher.Main.run(Main.java:1311)