I figured out enough to buy magic keys in Vesper and then get in Lord Robert's room using the "J" key for "Jimmy lock" but after getting past the room with the treasure and into the hall beyond it I get stuck. I couldn't find the rune in there and there are these purple squares that block my progress. Here's a screenshot of where I am right now:

IIRC you need to use a spell to dispel the force field.