Can't drop items/use items

I know I'm not lagging, I can chat and do all those things, but I can't change maps, use items, drop items/mesos, or anything. It doesn't give an error or anything I just can't. I've restarted maplestory multiple times and restarted my comp. Once it almost let me in the cash shop but because I got hit by a monster. I don't know... it just wont let me do anything.

Anyone know what's up?

I know I'm not lagging I can chat to buddies and I get their replies and such... I can move and jump but I can't use flash jump. I can see my chat the second I press enter.