I edited an existing page and added a link
[Setting up CVS with public/private keys for ext users]

It should up with a plus next to it to auto create.
I clicked then link added some text and click Add.
The page just comes page with no error message.

I'm assuming you are using the same Action to create a new page and create a new page from link just hiding the input box.
This means when the page return the error is added to an input field that doesn't exists.