OS:redhat advance server 3.0

today ,when i boot my linux server ,it a appeared follow error msg:

¡_¡_¡_¡_

configuring kernel parameters : dup2 : bad file descriptor
[FAILED]

load default keymap(us) /etc/rc.d/rc.sysinit : line 153 /dev/null read-only flie system


¡_¡_¡_¡_¡_¡_

¡_¡_¡_¡_¡_¡_

**an error occurred during the file system check
¡_¡_¡_¡_¡_¡_


it ask me press ctrl+d to reboot or enter the pass into the repair filesystem mode


when i login to the that mode ,i use fsck to fix it ,but it also gave me error msg : could not open /dev/null (read-only system file)



what cause this ?and how can i do now~

i want to use recuse CD to enable the network to backup my data ,but how cad i boot my server on now ?~

by the way ,i've done anyting with it before¡_¡_¡_¡_¡_¡_it happens suddenly^^^^^^