Sudo XXX is not in the; sudoers file. This incident will be reported.

The following is the solution:

1)Enter the super user mode. Is also the input " Su, -" the system will let you enter the super user password, enter the password entered the super user mode. 

[xxx@localhost ~]# su
Enter password:

Changed to root:

[root@localhost ~]#

More Details:

http://www.fatalerrors.org/a/user-is-not-in-the-sudoers-file.this-incident-will-be-reported.html