I just sent you a PM to see if if there was an issue and it sent sucessfully
When sending - was the name entered correctly? If typing in the name, after some letters a list of names should appear for you to select the user from - did you then try to select from the list?
Also be sure to enter a Subject line and a message more than 10 characters (I know a post must have at least 10 characters - I am unsure of PMs, but just to be safe
)