i had this really awkward problem:

2 months ago, i blocked one of my friends just because he kept flooding my msn messenger. but soon after he stoped doing that, i unblocked him. However, everytime i log on to msn messenger-that contact become blocked again. i kept unblocking it but after i re-login, that contact is blocked again? What's the problem?

hm, try norooms list cleaner, found: http://kaonet.net/page.php?id=81

People have been reporting awhile back that a certain contacts always blocked when they come online, and im pretty sure people here found out it was because their list had reached the maximum contacts allowed (even your deleted but not blocked contacts)

I used to have that problem with one of my contacts, but it hasn't happened for a long time now .

nope that noroom cleaner did not work, same problem..
well, maybe it's the server's problem?

Try to remove him (not block him) completly from your list and just add him again

you mean just delete that contact from my list, then add him again?
i tried that once, but i dont think that works too

delete each other, both run the listcleaner, readd each other.