Getting the same error after installing the new version. Main screen prompts for an image update and when you press the download image pack button you get two errors. By clicking "ok" for each error you are left with the download button saying "Cancel Download" however you can continue to start the game.
What I did to solve it:
1) Win + R: type %appdata%;
2) Search for tits folder;
3) Delete the ImagePack folder;
4) Open your game, download and install the Image Pack;
5) Enjoy
What I did to solve it:
1) Win + R: type %appdata%;
2) Search for tits folder;
3) Delete the ImagePack folder;
4) Open your game, download and install the Image Pack;
5) Enjoy
Annendum to this: if your appdata folder is on a seperate drive to your game installation, you can find it in C:\\Users\yourname\AppData\Roaming\tits and from there delete the image pack folder and re-download. This difference caused me no end of grief.