Drawing Dissapeared

[Rhone]

After spending considerable time on a drawing with multiple levels, I needed a new brush stroke. I drew what I wanted as the brush stroke, and created it. The new stroke appeared as expected, but the drawing my drawing, including the brush stroke that I had drawn (not the one that was now in the New Brush Stroke tool). I saved the file with a new file name, closed it, and opened the previous one with the vanishing drawing. The drawing was still gone. I am using Zara Extreme Version 2.0 e Dec 1 2005. Anybody have an idea of how and why this happened, and hopefully how the missing drawing can be restored?

I also discovered that I can no longer draw anything on any of the layers, or at least if I do everything is invisible.

Thanks in advance for any forthcoming suggestions!