This happend to me a few days ago... I prolly messed up my emote folder
The only solution seems to be to delete all your costom emoticons, and re-add them.
To delete all the old ones:
Go to C:\Documents and Settings\User\Application Data\Microsoft\MSN Messenger
Where C is your system drive and User is you user name, now choose what you think is the folder corresponding to ur email adress (can't remember how to figur uot that number
) Now delete the "CustomEmoticons" folder in it (THIS WILL DELETE ALL YOUR OLD EMOTES!) restart MSN and re-add your emoticons
I attached an adder program to make this easier (you can add a whole folder at once) found it at mess.be