Saving Logic Express files to & retrieving from a cloud

My music business partner and I are in different locations. Both have same version of logic express on our imacs. We both recently got burgled and this convinced us to save our logic express projects on a cloud. We chose Dropbox as it works with all types of data. I save the whole logic express folder(s) to Dropbox by dragging it there. However, when Steve opens it from Dropbox, it won't open. When we retrieve from Dropbox, should we open directly from Dropbox or copy the whole folder onto our imac - and THEN open it? Any ideas would be appreciated. Thank You.