Playing iTunes from External Hard Drive in new User Account

I used to own a macbook and I played my iTunes library from an external hard drive. I've recently upgraded to a macbook Pro and I copied all data, profiles etc across from my old macbook into a separate 'user account' on the new mac Pro ("Old Account"). I have also created a separate second account in the mac Pro ("New Account"). I am able to play my iTunes library from the external HD in the Old Account, but not in the New Account... In the New Account, when I launch iTunes while holding down the option key, it gives me a choice to choose an iTunes library. On the external HD I have an iTunes Media and iTunes Music folder, however, regardless of which folder I select, I get the following message: "An iTunes library file could not be found in the folder "[Name of Folder]". Please choose a different folder." ... Please can anyone help?

Many thanks in advance!