Can't display an offline map from SQLite database

[CactusPie]

I'm having trouble displaying an offline map from an SQLite file on an iOS device. I can only see a white rectangle as a result. I'm sure that the database file is loaded correctly, since running a test query returns expected results. I have followed a sample project available here on GitHub, but nothing works. I'm all out of ideas. Could anyone please help me?

Here is the source code for my ViewDidLoad method: http://pastebin.com/gTPp7XMc
Here are the map files i tried to use:
http://cactuspie.eu/tiles.db
http://cactuspie.eu/mymap.sqlite

Any help would be greatly appreciated.