Catherina is a mistake because it is not Spanish; the only correct Spanish form is
Catalina.
In some Spanish speaking countries, basically Mexico, some people use the Italian form
Caterina, known through saint
Katherine of
Siena (santa
Caterina de
Siena), but misspelled as
Catherina by English and French influence. So it is possible to find
Catherina used by Spanish people, but the form is not Spanish.
About the nicknames or variants of
Catalina, the only nicknames that I know are Cati, Catita and Catana. That is not surprising since it is not as popular as the name in English.
Lumia
http://onomastica.mailcatala.com