I am experiencing a pretty disastrous bug.
It started a few days ago when I tried to create a new KS level using the editor. I was at this point using the most-recent-but-one version of KS+. The level name I created had a colon in it, along the lines of 'Shooby: sha Dooby da Wooby', which is the only odd circumstance I can think of. I was creating a KS+ level.
Anyway, the editor generated a totally blank level; it didn't contain the default new-level first screen and then I realised that the world.ini was completely blank. Further investigation revealed that the editor hadn't even generated a world folder for the level. A later check revealed that the level isn't appearing in the KS+ player level directory.
At this point I reset the editor and tried creating the level afresh with the same title. I got the following error message:
DirPacker Error: Directory Exists
Well ok, I thought, that possibly makes sense at this stage. Having lost motivation for starting a new level by now, I gave up for a few days.
Since then I've come back to it and had the problem persist. I tried recreating the level with the same title and got the same error message. Then I decided to give up on that title and tried to create a level with a different title; I got the same error message. I went so far as to randomly bash keys to try and generate a level title I couldn't possibly have entered or installed before but got the same error message again.
Since then I have switched to the most up-to-date version KS+ and re-downloaded the most recent level editor. I've tried creating a vanilla KS level instead of a KS+ level... bug still persists. I wanted to try creating the level with the vanilla editor but my virus checker has now picked up on the Trojan in there and kindly deleted both my copy and my backup without asking my permission. I could probably (possibly) bypass the problem by C'n'Ping another level's world folder and clearing its contents for a fresh start... I'm out of ideas for a fix, short of reinstalling vanilla KS (I haven't tried that since the 'Dragon Myth' ball is now back in my court and a few hours' work from release. Once it's done I'll come back to banging my head off of this problem).
I don't know if this is related to the two minor bugs I reported a while ago that you couldn't reproduce, though downloading the most recent version seems to have fixed the ambience-consistence-after-reset problem I was having.