gdm greeter crashing

[Yonas Abraham]

after i input my user name and hit enter, instead of getting a password
prompt I get "The greeter program appears to be crashing. I will attempt
to use a different one"

I even created new user, but it is independent of a specific user,
actually even if i hit enter without writing a user name it still
crashes. 

I am using FC4 uptodated

any idea on where to look, i have looked on /var/log/messages