how do i delete a vip mail box?

Actually, there is no need to mess with the mail folders with Finder and Terminal. Just click on the disclosure triangle next to the VIPs mailbox to expose the list of names. Either:

(1) control-click on each of the names and select Remove from VIPs from the contextual menu until all the names disappear from the VIPs mailbox. Quit Apple Mail then run it again - the VIPs folder should have gone.

Or:

(2) click on each name and any mail within that name. Click on the star next to the name in the mail; the name should disappear from the VIPs mailbox. Sometime, if you deselect the star from the last name, the VIP mailbox would disappear from the left pane, or at the most, left with no disclosure triangle. If that's the case, simply quit Apple Mail and run it again - it should disappear.