Why the system freezing ?

[cj]

I'm newbie in Debian.When the install process go to the step build the 
XF86Config file,it will
return "can't build the file" and show the "build XF86Config file" again.But it 
freezing in this
tty.The process is to run the svag postinst script.Why?
Another question,how to change the builtin 320x200?
Thank you.