Spanish language files are not included with the SCLogin module. However, you can easily create this file by copying:
/languages/en_GB/en_GB.mod_sclogin.ini
to
/languages/es_ES/es_ES.mod_sclogin.ini
and then modifying the strings as necessary. The other file you may want to copy and modify is en_GB.com_jfbconnect.ini. If you run into any issues though, feel free to let us know.
Thanks,
Alex