I was having issues with removeWorldModel too some time ago, so I moved it to client-side (instead of server-side) and eveything worked fine.
addEventHandler ("onClientResourceStart", resourceRoot,
function()
removeWorldModel(16613, 10, -346.671875, 1595.078125, 79.6640625) --object
removeWorldModel(16614, 10, -346.671875, 1595.078125, 79.6640625) --LOD
end)