Error in opening a document with Mac

Hi all

we're facing with an issue linked to opening a document with a PC Mac.

With Windows op system it works correcty.

We ha already noted this:

and we have already made several tests on this changing the syntax of the path in order to follow what suggested by the assistant, but without a positive result.

As a result when we make double click on the document in order to open it (wit a Mac PC):

we get this error:

Does anybody met this situation?

Suggestions are appreciated.

Thank you in advance.

Stefano