Hi ,
To reset the admin password you need to console into appliance. If you don't remember console password then only option is the reset it using recovery cd,
http://www.cisco.com/en/US/docs/net_mgmt/cisco_secure_access_control_server_for_solution_engine/4.1/installation/guide/solution_engine/admap.html#wp1038722
Also if you can't login to GUI after the upgrading acs to 4.1 then you need set up GUI admin via console,
To add a GUI account that the CLI administrator can use, use the add guiadmin command.
add guiadmin [admin] [password]
Regards,
~JG
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