could not find framework in eclipse RCP application -

I have developed an Eclipse RCP application that I am calling from my Java program.
When I run my Java program from Command Prompt (Window) it is working perfectly and giving results.

But when I integrated in Eclipse with Ant Build Script 3.2 is offering the following problems:

  Log org.eclipse.core.launcher 4 0 December 02, 2009 10: 53: 17.608 Message Exceptions Eclipse Stage: Stack java.lang.RuntimeException: The structure at org.eclipse.core could not be found. launcher.Main.getBootPath org.eclipse.core.launcher.Main.basicRun (Main.java:174) on org.eclipse.core.launcher.Main.run (Main.java:395) (Main.java:704) on xxx.xxx.xxxx.MyCodeGenerator.main (MyCodeGenerator.java:13) on sun.reflect.NativeMethodAccessorImpl.invoke0 (Native method) sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:39) on sun.reflect.DelegatingMethodAcc on essorImpl.invoke java.lang.reflect.Method.invoke (Method.java:585) to (DelegatingMethodAccessorImpl.java:25) org.apache.tools.ant.taskdefs.ExecuteJava.run (ExecuteJava.java:202) organization on .apache.tools.ant.taskdefs.ExecuteJava.execute (ExecuteJava.java:134)  

would you please have that can help me probable cause of this error.

As noted in you, you:

• platform plugins You only want to add to your list of dependent plugins, depending on your convenience,

(see for example)

Ensure that you have your own RCP (see) "Plug-in valid" before Onc. With the launch configuration dialog, in the "Plug-ins" tab, you can click on the "valid plug-in" button, which you can click to verify that all the dependencies of the "selected" plug-in are satisfied. .
If there are some errors, you can click on "Add required plug-in."> "To fix the error.