Crystal Error: System.Runtime.InteropServices.COMException (0x8004180B): Document has not been opened.

You only get this error is you are running SAP 9.3 PL04 or higher

Reason and how to fix:

This is due to a change from SAP where they updated Crystal Report runtime to a new version. Please see this article for the full details on how the different Boyum product resolve this problem: https://support.boyum-it.com/hc/en-us/articles/360001157008