No admin user after restore a virtual server

I can't login to webmin with the virtual server's admin account and password after restoring the virtual server.If I login with root account, I cant't see the option to add new administrator accounts under the "administration options" menu in the restored domain. In the Webmin users module I don't see the domain admin account anywhere. The problem is only in the restored domains. If I create a new domain, I can login and I can see the option to add new administrator accounts and the account is listed in the webmin users too. I tried changing the password for the virtual server's admin account but I still can´t login to Webmin. ¿What can I do to set again the admin account for my restored domain?. The command "virtualmin create-admin" says me that the create-admin.pl file is not found. My Virtualmin version is 3.92 GPL. Thank you.