ASA 5510 unable to find disk0:/asa722-k8.bin (URGENT) Please

Hello , I have similar problem with my ASA 5505 .
When I upgrade IOS , I made mistake and deleted flash .... after that I booted from tftp server and get up IOS an disk0: . "Everything" is OK , the router working ....., but when need reboot of ASA 5505 , my router does not boot from disk0:asaXXX.bin and load ROMMON# and I have to set it to boot from tftp .
I followed the commands :

asa5505#boot system disk0:asaXXX.bin
asa5505#reload
.....
after restart

asa5505#sh ver
Cisco Adaptive Security Appliance Software Version 8.2(2)
Device Manager Version 6.2(5)

Compiled on Mon 11-Jan-10 14:19 by builders
System image file is "tftp://192.168.1.1/asa822-k8.bin"
Config file at boot was "startup-config"

ASA5505 up 16 hours 21 mins

Hardware: ASA5505, 512 MB RAM, CPU Geode 500 MHz
Internal ATA Compact Flash, 128MB
BIOS Flash M50FW080 @ 0xffe00000, 1024KB

Encryption hardware device : Cisco ASA-5505 on-board accelerator (revision 0x0)
Boot microcode : CN1000-MC-BOOT-2.00
SSL/IKE microcode: CNLite-MC-SSLm-PLUS-2.03
IPSec microcode : CNlite-MC-IPSECm-MAIN-2.04
.......

and every time the router wants to boot from tftp: , that is absurdity .

Do you have any ideas how I repair this problem please ???