I go to
1. Content
2. Article Manager
3. Click the new button
4. Enter title
5. Select section
6. Select category
7. Enter article text
8. make sure the article is published and on the front page
9. click save or apply
other menu options are creating this error, but it happens randomly. Creating an article make this happen every time.
I'm also having people signing up to my site and getting an invalid token.
Well, it seems that you are adding Articles correctly.
But since both these issues are related to the Joomla core and not the template you may be using, you're probably better off searching or posting on joomla.org.
I got plenty of hits for both, but I can't tell you which solutions apply to your particular situation.
Then also make sure the correct owner is assigned. Sometimes a host moves files and the owner gets assigned to them instead of you and can cause them to be un-editable.