"Click here to add him or her now" did NOT work

Someone added me into his contact list. and then his name/email displayed in
my contact list (i didn't remember whether i grant his request)

during my vocation, he sent me an offline message, and i received it today.
but when i tried to reply, i found i couldn't send offline message to him.
upon the conversation dialog, a warning message said " is not
in your contact list. Click here to add him or her now". so i DO click "Click
here to add him or her now", but it didn't work. nothing happened, and i
can't send offline message to him either (i didn't get a chance to send a
online message to him as we have 8-hour time difference)

so, is there any functional problems around it?