The translation of this is impossible in Spanish and even in English it is shaky, especially when the variable is used. As example translation of the string "Invalid secondary name server #%i selected".
In English it is linguistically weird to speak about a primary, first secondary, second secondary or third secondary server. It would be better to speak about first, second, third, fourth etc.
What is weird in English is utterly rediculous in Spanish. In Spanish nobody says first secondary, second secondary. Unless you change things I cannot find a good way to the example string to Spanish and I am sure there are other languages where is not acceptable.