Hello!
That seems to be an issue with the savefile, I'm trying to fix it.
It seems at some point the save got corrupted and now it throws an error when loading the game, if you have more than one characters try moving their saves from the save folder to another one until you find which one is the problem. It usually is a file that suddenly got empty.
The saves are located at c\users\yourusername\appdata\locallow\SkyflareStudios