first when you come on IRC don't expect people to watch the channel every 2 minutes, stay there a bit longer particularly "during night".
You are describing how I was welcomed by my first Tiki installation. I was using Windows at that time and it's a bug about the temporary directory. The page Admin General has the theme setting and the temporary directory setting. Anything you would change there would "reset" your site. If I remember right clearing totally the text field and saving should stop problems (otherwise this problem is mentioned at several other places around here).
BTW, I think this was fixed, maybe you're using an old version?