I will investigate this and publish an update to fix this asap. Database error means your client was unable to query the database, maybe because a connectivity issue, etc. Not showing the captcha was unfair. I need to add a button to generate a new one to prevent this softlock. Sorry
I am not in front of my computer until next week. If the dungeon is now completed I will generate a new one and add your name as a winner (write here your ingame name)
Thanks for report that