You don’t absolutely have to use ZIP. If you actually have a way to download a folder from a server, which I think you can on dropbox, then you could just move the AUP file and the _data folder to the server, then download the AUP file and the _data folder to the other computer. But without the AUP file there is no way to know the correct order of the AU files.
ZIP is much simpler for most users. If the ZIP application works correctly it should retain the folder structure for you.
If all the tracks start at time zero you can do it easily using File > Export Multiple… .
If some of the tracks don’t start until after zero, see here: Save each track in project, but *preserving* blank space - #2 by Gale_Andrews .
That structure could not be opened even if you had the AUP file.
The structure of the _data folder for the project is that it has an “e00” folder. Inside “e00” are one or more “d” folders starting from “d00”. Each “d” folder contains up to 256 AU files.
There should not be any text file, only an AUP file. Attach the text file here. Please see here for how to attach files: https://forum.audacityteam.org/t/how-to-attach-files-to-forum-posts/24026/1 . The text file may be the AUP file.
Generally it sounds like your zip application is completely broken. You can use the Mac to zip files (it is called “Compress”). See: http://support.apple.com/kb/ph4048 .
Yes if you correct the structure of the _data folder and if you have the AUP file. The AUP file must have same name as the _data folder, for example “My 7 tracks.AUP” and “My 7 tracks_data”. The AUP file must be in the same folder that the _data folder is in. The AUP file must not be inside the _data folder.
I would suggest you go back to the other computer and export separate WAV files for each track, or zip the project up again with a proper zip compression utility.
Gale