Allain,
You must have forgotten to put "superuser" on the end of the command line when you changed the "admin" password. It's a common mistake.
Anyway, here is what you need to do. Reboot the CSS. When the box begins to go through it's boot cycle, you will need to hit any key during the 5 second countdown to get into the Offline Diagnostic Menu. Once in the menu, choose these options
CS-x00 Offline Diagnostic Monitor, Version x.x
M A I N M E N U
Enter the number of a menu selection:
1* Set Boot Configuration
2. Show Boot Configuration
3* Advanced Options
4. Reboot System
At the above menu select Option 3. - 'Advanced Options'
A D V A N C E D O P T I O N S
Enter the number of a menu selection:
1. Delete a Software Version
2* Security Options
3* Disk Options
r. Return to previous menu
At the above menu select Option 2
S E C U R I T Y O P T I O N S
Enter the number of a menu selection:
1. Set Password Protection for Offline Diagnostic Monitor menu
2. Set Administrative Username and Password
r. Return to previous menu
Choose option 2 (NOT 1) at the above menu.
You are now prompt for a new admin equivalent username. DO NOT use "admin" here as the config will override what you do here. Use something like username: allain, password: allain
Once this is complete, back out to the main menu and reboot the CSS. When the CSS completes it's booting up, login as allain/allain and then rerun the password change function on the CSS that you originally users to change the password, but DO NOT forget to include "superuser" on the end of the line.
that should do it
Regards
Pete Knoops
Cisco Systems