[XeTeX] Installation problem

[Christophe DAMAS]

Hello,

I've installed xetex using i-installer. But when I try to typeset a 
document I get the following message :

This is XeTeXk, Version 3.14159-2.1-0.88 (Web2C 7.5.2)
  %&-line parsing enabled.
kpathsea: Running mktexfmt xetex.xfmt
mktexfmt: No such file or directory
I can't find the format file `xetex.xfmt'!



That's true because  there's no xetex.xfmt file in tetex directory 
hierarchy. I've tried to build this file using xeintex, but I get a 
error message (BUS 56).

I'm working on macosX 10.3.5.

Does anyone has a suggestion for me, where is the problem ? Does anyone 
has a list of file that are compulsory.

Thank you.

Christophe.