Send to Layout greyed out (on mac)

[Edson]

two strange things are happening to me. I am not sure it is relevant to the problem, but I have my files in a dropbox folder. what happens is that in sketchup Send to Layout is greyed out and in Layout I cannot save the file as I get a weird message (see attached).

has anyone encountered this problem? any ideas as to how to solve it?

thanks.