Hi Giuliano,
You can follow the instructions to get rid of the client automation error. On your browser you need to allow active x control, try adding your ariba login URL to trusted sites. You can alo log a request with ariba support team to get it resolved. Ensure you are using a supported browser version.
Once you solve that issue, you should be able to schedule the report to your email id. Also, once you create a report and save it you can give permissions to specific users/groups to that report provided they have basic reporting permission.
Regards
Vilas