Boot problem with freebsd 5.3

[cell]

hello , i have problem when i boot with freebsd 5.3 since i have had a power cut .The message of the error is : 

error 16 Iba 191
No /boot/loader

FreeBSD/i386 boot
Default: 0:ad(0,a)/kernel
boot: error 16 Iba 191
No /kernel

I don't know if the hard disk is endommaged but i don't think.How do for boot in freebsd ?