On Thu, 7 May 2009, Amaël Broustet wrote:

> Ok I just put in my essai.tex size=24pt istead of  size=24 and there
> were no more errors.
> But the generated pdf file is blank (2 pages wihtout test or graphic).

Simpleslides comes with a test script. Try the following

   mkdir styles
   mtxrun --script simpleslides --styles=BigNumber --engine=context

This will create BigNumber-blue.pdf and BigNumber-red.pdf in the styles 
directory. Are these files correct?

Aditya