Pascal,
In the Preferences, under "PlanetPress Image 1", put your admin's email address there, and then make sure you check the proper check boxes to send the corresponding log files. Also go to "PlanetPress Image 4", and make sure your SMTP is properly configured there.
With these options, this should work properly. However, it's important to note that this apply to "Image", and not "Workflow". So if the error happens on the Workflow side, even if it has an "I" error code, you might not receive an email. Check the service console, and see if the error is on Workflow or Image. This reports errors that happens to Image.
Regards,
Raphaël Lalonde Lefebvre