How come everytime I add a user with a number at the end of it its invalid?

e.g.

username: sites1
pw: hello

it adds, it passwords
but when i ftp localhost
sites1
hello
it says invalid login

??

Since when can we not use numbers at the end of usernames ?

it works if i dont add a number
my os is rh 7.1 seawolf

n/m

It sounds like you have problems with the way your FTP permissions are set.
Can you login Via a Telnet/SSH section with the new user? If you can they its a problem with your FTP Server.