try turning off your maphack. all my stupid friends who dont appreciate the game for what it was made for who use maphack have had your "problem" one time or another. just shows you playing legit is better.
just for good measure.. in case he isen't using maphack: you can't insert things into sockets when the item is being worn by your merc. If the item is in your inventory then follow the suggestions above and shut off maphack.
In fact, go one better and delete maphack from your computer. you don't need it. Maphack is like spellchecker on your computer .... makes you lazy and still doesn't get everything right.
