Suddenly can`t see scenarios (cfgs?) when setting up game

[salamis]

Operating system, including its version.
Version of Wesnoth, including the configured language.
A step-by-step walkthrough of how to reproduce the problem. If the problem can’t be reproduced, our ability to identify its cause and fix it will be severely limited.

OS: Windows 7 Lite
Version of Wesnoth: 1.12.5, language: Spanish
Error: Everything was fine, then suddenly when I tried creating a multiplayer game all of my scenarios disappeared (sandbox, wc, etc.). I tried deleting and re-downloading them, and copying them into different folders, but nothing helped. This apparently happened after I saved a replay for a sandbox 1v1 I played. Any ideas on what could have happened?

Thanks.

[Pentarctagon]

By "scenarios" do you mean all maps available when creating a match, or just the ones from add-ons? Also, what does your stderr.txt say?