Can you specify which version of blenderseed you used. For newer versions you can see the details in the user preferences of blenderseed (see screenshot). And the output of the terminal would be useful.
Im useing the latest version 1.0.0 of blendeseed.
We have only seen something similar when one switched to viewport preview render (ipr render) without having a camera in the scene. A camera is required to render a scene.
This has been fixed in blenderseed. Now a camera is automatically inserted if there is none.
Can you try this (newer) version for Blender 2.79-Windows:
In general, if you encounter a bug, please provide as much information as possible about the used plugin-version, the error output in the Blender system console when the bug occurred and the steps taken.
We are grateful for all bug-reports and try to fix them quickly.
We don’t see this behaviour. Can you make a clean reinstall of blenderseed (the version from the link above) after removing all old remnants of it.
It works only with Blender 2.79b official release version, so be sure you use not an earlier Blender version.