`sudo userx` returns `sudo: userx: command not found` , why?

just installed this Linux disto ver 13.04 installed Xfce 4.0x got it running just fine then for some reason that good'O sudo stopped working all by itself why? I now type in sudo and this is what I get

Wed Oct  2 15:23:06 CDT 2013
[15:23 userx@bw ~] > sudo
usage: sudo [-D level] -h | -K | -k | -V
usage: sudo -v [-AknS] [-D level] [-g groupname|#gid] [-p prompt] [-u user
            name|#uid]
usage: sudo -l[l] [-AknS] [-D level] [-g groupname|#gid] [-p prompt] [-U user
            name] [-u user name|#uid] [-g groupname|#gid] [command]
usage: sudo [-AbEHknPS] [-r role] [-t type] [-C fd] [-D level] [-g
            groupname|#gid] [-p prompt] [-u user name|#uid] [-g groupname|#gid]

            [VAR=value] [-i|-s] []
usage: sudo -e [-AknS] [-r role] [-t type] [-C fd] [-D level] [-g
            groupname|#gid] [-p prompt] [-u user name|#uid] file ...

so I then type in this

[15:23 userx@bw ~] > sudo userx
[sudo] password for userx: 
sudo: userx: command not found

[15:23 userx@bw ~] > 

and that is what I get after I type in my password

what is going on here? how am I to install anything? wish they'd never messed with su installed the root user account by default then let you create users