Your problem must be one of procedure.
When making the second bar, start from scratch, don't try to copy from the first bar. The second bar should originally have the 4 default menu items on it.
Lets assume you did that, when you go to save the menubar, it must get a different name than the first menubar, it could defaulting to the same name, and writing over the first one.
Assuming also you are not using FP or Dreamweaver.
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