Melissa, the warning message you posted is showing that when you export your project, you are selecting the wrong location, so that you get the exported files inside the exported files inside your exported files inside... you see what I mean?
The correct way of doing it would be (as an example): If I want to export something to Desktop, when asked to select the folder, I select 'desktop'. The programme creates a folder on my desktop by the name of 'whatever-project_exported'. Then, after a bit more editing, I save and export again. When asked to select folder, I select 'desktop' again,
NOT the previously created 'whatever-project_exported'. If I do, I get a new 'whatever-project_exported' inside the first one.
So, at each export I always select the 'desktop' as my destination, and the programme will overwrite the previously exported files.
However, if I don't want to have them overwritten, I still select 'desktop', after having
saved as with a new name, like e.g. whatever-project-2 or so.