Password Revovery CISCO1600

Hi
My problem is when I change the registre field boot to 0x2142 and I reboot the router, I can acces to enable mode, and I can make a copy of the startup-conf to running-conf, but I can not enter to the terminal configuration mode, when I execute the command ‘configure terminal’, I get the message : ‘command autorization failed’ ???

thanks for your help