I think the translation of the cardinal numbers used for birthdays is wrong. In English, there is 1st, 2nd, 3rd, 11th, 12th, 13th, then again 21st and so on. In German, there should only and always be a dot behind the number: 1., 2., 3., 4., 11., 21. Right now, the birthdays are using "ter" (63ter), which is how the dot is pronunced. Writing it like this is silly, IMHO. I always edit the language files for this, changing "%iter" to "%i.".
Maybe this could be changed in the next official version?

Ich finde, die Ordnungszahlen für die Geburtstage sind falsch übersetzt. Es gibt kein "1ter" oder "102ter", da ist nur ein Punkt nötig und richtig. Vielleicht kann das bei der nächsten Überarbeitung geändert werden?

That's the way the Finnish translation shows them too so I'm fine with this kind of change. If there are no objections you can go ahead and upload the changed language file to the website. It will be added from there to Rainlendar when the next version is released.