I don't think anything but a regular socketable could have four sockets. The 1.10 shouldn't matter a lick.
From the Arreat Summit:
Spirit 4 Socket Swords/Shields Tal + Thul + Ort + Amn
So that's not it either.
Got me stumped... Have you tried any of the other runewords to see if they work? Are you starting your game from the shortcut rather than the start menu (if you bypass the shortcut you wont activate the RWM)? Are you absolutely sure you placed them in the sheild in that order?
Show us what ATMA reports for the shield and that might be a help.
ED: It wouldn't come up with "gemmed monarch" in the game, it would simply call it TalThulOrtAmn without a rune word above it.