Do you still have this error using another save file, if you have any? I tried replicating it, but it seems to work in all the versions of mine currently - I think it might be have been an error caused by playing a previous version with bugs that hadn't been fixed yet (current one should be good to go!)
Apologies for the delayed response, but yes. Here's a screenshot of my last attemptAnd you're playing the browser game and not any of the downloadable versions, right?
I'm due to make a new update / add new contents to this game in a day or so (likely this Friday) - I'm pretty sure it's some weird saving bug that might be using an older update for some reason. If the new game still has this bug, please try playing it on a different browser and seeing if it's got the same error? There might also be a few incompatibility things with browsers that's the issue, but I have to eliminate all the possibilites first before I can focus on which one!