[vtkusers] SetSizeInternal in vtkJavaAwt.h

[Lichan.Hong at parc.com]

I am writing my application in Java, calling VTK 4.0 through JNI. 
When I run my application, I keep getting the message "Error
locking surface" and nothing appears on my window. 

I found out that this message comes from "SetSizeInternal()" in 
Common/vtkJavaAwt.h. The following is a piece of the code:
		lock = ds->Lock(ds);
  		if((lock & JAWT_LOCK_ERROR) != 0) 
    		{
   			printf("Error locking surface\n");
    			awt.FreeDrawingSurface(ds);
    			return;
    		}
For some reason that I don't understand, locking the 
drawing surface fails, leading to the error message. 

Any helps would be greatly appreciated.