Taking the Holy Grail should not have had any effect on the teleporter pads, nor would anything else you could do in-game.
Do you still have the teleporter scrolls in your inventory? Can you teleport to the burial grounds teleporter pad? Did you try clicking on the teleporter pad symbols anyway, even though they were no longer shown on the map as activated?
Do you have a recent save you can reload, where the teleporter pads are working properly?
Check your messages (click 'My Stuff' in the top menu bar, then 'My Messages').
