Can’t Add Contact on Windows Live Messenger =\

my friend added me on messenger.. i accepted on Hotmail website.. so i can chat with him on site.. but still can't see him on my windows live messenger.. and when he talk i get the messaging window.. i try to type and send something... it says the following messages could not be sent... and it won't send.. however.. when i try login from my phone.. (eBuddy) i can see my friend and talk to normaly... but i want to talk from computer on windows live messenger.. any thoughts?