Fax Bob received while he was shaving

I'm confused about this one. One would think the fax was from Charlotte because the next scene was Bob going downstairs then outside where he makes the call to Ms. Kawasaki to accept the "Japanese Johnny Carson" show. Then he opens a note (presumably the fax) which is a map to somewhere, with the text, "Call me if you get lost, Charlotte."

But where is the map to? Was this another invitation for him to meet her and friends somewhere? Somewhere he ended up not going that evening? Thus making Charlotte's next morning discovery that Bob slept with the lounge singer even worse? Worse because he didn't show up for her but slept with the singer?

But if this was the case, the movie didn't really convey it that well, in my opinion. Or did the fax have something to do with the Japanese folks downstairs whom he evaded when he exited the elevator then proceeded outside to make phone call and review the map?