check for exception when looking up slicing criterion

		final EDG edg = new EDGFactory(last).createEDG();

		final SlicingCriterion slicingCriterion = new SlicingCriterion(a.file, a.line, a.name, a.occurrence);

		try {

			final Node SC = edg.getNode(slicingCriterion);

			if (SC == null) {

				System.out.println("Error: the slicing criterion could not be found! " + slicingCriterion);

				System.exit(1);

			}

		} catch (IllegalArgumentException e) {

			System.out.println("Error: the slicing criterion could not be found! " + slicingCriterion);

			System.exit(1);

		}

		final SlicingAlgorithm slicingAlgorithm = a.getAlgorithm(edg);

		final Set<Node> slice = slicingAlgorithm.slice(SC);