How to fix Multiple added entities may have the same primary key in EF?

Question

I am using a Database table whose structure is like this

RejectID int Primary Key
RecordingID nvarchar(500)
RejectedBy int

On one button click I am trying to add object like this:

 public void btnReject_click()
  {
          RejectedRecording currentRR = new RejectedRecording();

            currentRR.RecordingID = "hbi123kjubj27676";
            currentRR.RejectedBy = 5;

            objOmniPCXRecordEntities.RejectedRecordings.AddObject(currentRR);
   }

on other button click I have called Save changes like:

public void btnSave_click()
  {
        objOmniPCXRecordEntities.SaveChanges();
   }

It works fine if I only try to add one object but in case of second record exception occurs which is

Unable to determine the principal end of the 'OmniPCXRecordModel.FK_RejectedRecordings_RejectedRecordings' relationship. Multiple added entities may have the same primary key.