I tried, without any success, to update to 5.0.2 under Joomla 2.5.14, receiving Error 500. It seems the same problem like here:
https://compojoom.com/forum/ccomment-core/18146-error-500-after-activating-ccomment-core#22393
I tried to create new settings for com_content, as there are none after the update:
http://awesomescreenshot.com/0271ws7466
It does not save the settings.
Please let me know, what kind of changes (related to the linked post) you did.
Okay I made the changes to the settings table and the comment table and it is now working.
As we do have a live site running, I would have to know exactly what changes you made, unfortunately I can not give you access to the MySql server.
Thanks for any feedback!