inable to boot with fedora

[Alilou_Linux]

Hello,
In the last time I have updated my system (fedora), therfore I have the
following problem:
Juste in the moment where the system must give me the hand to introduce my
login and my password, it show the fellowing message and it bloc and I can
do anything.
the message is displayed in french, its translation in english is:

    There is an error at  the loading of the Bluecurve topic.
    Cannot recongnize the format of the file of picture for the file
"/usr/share/gdm/themes/Bluecurve/icon-language.png ".

Now, I can't boot with Linux (fedora). So, do you know how to resolve this
problem, please?
Thank's.
ALILOULINUX.