RPG Tekkit

Ok I've been googling and looking for half of today and I can't find the answer. When ever a non OP player on my server tries to move something around in his/her inventory, or from a chest to his/her inventory. Pretty much drag and drop anything, the item doesn't show up in hand, then when they click again in a blank spot and it shows up in hand. Then they click a 3rd time and it is dropped from their hand where they clicked the second time. It doesn't happen to OPed players, does anyone have any experience with this bug? I'm so frustrated with this thing right now. Thanks in advance. I fixed it turns out it was a custom plugin bug.

Have you tried www.razorservers.com? They are located in Philadelphia, and my servers are hosted there. They seem to have a really good connection speeds, and the prices are really good for dedicated servers.