When adding a new corrency, it is no longer shown in the UI panel, and therefore it is not possible to edit it, it exists in the database but does not show in the panel, causing failures for not being able to edit or remove it.
I just tried on demo server on ASTPP 5 and that seems to be working. Did you try on demo server with 5.0?
This happens in version 4.0.1
I only managed to solve it, manually editing in the database, because in the panel it doesn’t appear.