There is no confirmed location of Kummerland, it seems to be just likely an allusion from the book Jim Knopf und Lukas der Lokomotivführer which was released in 1960. The parcel has 3 bodies and of course a label which has both a name and a city, because as you know in the past we had to write the name and also the city of the player on the label. Kummerland was known as the the city of "the thousand dragons" and Ms Mahlzahn is a reference for a character, which is a dragon, named Frau Mahlzahn, his hobby is buy children to teach them and torture them. Land of dragons reminds me of Draconia, but this might not be related.
Source- Tibia forums: [MISTERY SOLVED] Ms Mahlzahn, Kummerland
Related to- Who is Ms. Mahlzahn?