[Newbie]screen error

[sjravelaer]

l.s.,

after i type startx at the command line i get the next error message: 

data incomplete in file /etc/xf86config

device section ``primary card'' must have a driver line

(ee) problem parsing the config file
(ee) error from xf86 handle config file()

fatal server error:

no screens found

x connection to :0.0 broken (explicit kill or server shutdown).

can anyone tell me what i've done wrong or what has gone wrong?

thanks