*Shrug*
Last month's compressed version was unplayable because of missing clue images. That's a fact. I can choose between taking your word about whether or not you test sufficiently, or look at the myriad of bug reports I had to waste time on last month. My experience as a software developer makes me go for the second choice every time.
If you enjoy making mods of games, I can't really stop you. I would appreciate it if you clearly mark them as such, however. Put a disclaimer on the main menu where you show that it's a modded version (add your name/nick there too if you want, as long as you don't remove my own credits in the process. You did work on the mod, after all). This way there will be no confusion among players and I can more easily help them figure out if they're playing my version or your version.
I can't really tell why you're getting that error, I'm afraid. It occurs when the game is trying to tell you about something that got updated in your game since the previous version. Ren'py complains about not being able to draw text, which is odd. I suspected that it might be related to you have saved in the ability screen while on a menu, but even replicating that situation perfectly, I didn't get that same error myself.
If you still have 0.25.0, you might try loading your game there and saving in a "safer" spot before moving over to 0.26.0, preferably not in one of the menus or the map. It shouldn't normally be a problem, but desperate measures and all that...
Never heard of this issue before. Are you on PC, Mac, or Android? If on one of the first two, do you have a dedicated graphics card?