NetView for NT

Two questions:

1. I built a menu item with MIB Tool Builder.  I am getting an
error with it now.

Error: Tool 'menu_item' is not a valid MIB tool.  The menu
registration file was incorrectly modified.  This tool cannot
be modified or deleted using the MIB Tool Builder.

How do I delete this menu item now?

2. Why do I not get any values with some MIB Tool Builders I
created?  If I do a manual browse on some MIBs then I do get
my values, but not when I use the MIB Tool item I create.

Thanks,

Larry