FOSS gamedev and creative worlds

Hey people, I'd like to post a topic and say some problems of mine trying to reach the Single-Player feature.So very first of all, whenever I make a new world and enter it the map, doesn't load at all and also gives me this message:
ERROR: Could not open database file
So, if you have had the same experience and you know how to fix this please post a comment
Thank you for your time.

Is your antivirus or firewall program blocking Minetest somehow? What version of Minetest are you using?

Topics like this are better created in the section of the forums devoted to bugs and problems.