Somehow they always get German and Dutch confused. They're not *that* similar.

But I agree, they were singing "Sinterklaas kapoentje", but only in German instead of Dutch. Sinterklaas is the guy who Santa Clause is based on. If you say Sinterklaas aloud in Dutch, it even sounds like Santa Clause.

Anyway, it loosely translates to:
Dear Sinterklaas
Put something in my shoe
Put something in my boot
Thank you, Sinterklaas

Also, instead of hanging a sock by a chimney, we ( the Dutch ) put our shoes next to it.