I thought I'd better write this as a warning to those who add taxonomies to their menu. There is a bug in WordPress when it comes to doing this.
Usually, when you add an item to the menu, but then remove the item, it will utomatically be deleted from the menu. however, it does not do this with taxonomies.
Therefore, if you add a taxonomy to your menu, and then delete the taxonomy, you will no longer be able to load in your menu in admin. It will just give you a white screen with a bullet point at the top left. The only way to get away from this is to find that taxonomy menu item in the database (which I found impossible), or delete the entire menu that the taxonomy was in from the database and start over. Not a pretty job either way.
Just make sure you remove the taxonomy from the menu before deleting it.
This is not an error with CustomPress, but WordPress itself.