Permlink issue

Dear all,

I am newbie in wordpress.
Could you please help me on premlink issue?
My wordpress is installed on local server.

I changed Permlink settings from “Plain” to “Post name”, then I cannot create new pages.
When I create new page and click Preview button, I saw it went to a link that is plain link (with ID in URL) and showed me an error 404 page.
When I Publish the page, it showed me “Updating failed. Error message: The response is not a valid JSON response.”

I followed some advise from google.
1. I changed the another permlink settings and save it. Then chose “Post name” again. It still act the same.
2. I checked .htaaccess file, it looks normal to me.

Could anyone give me advise what I should do further?
Thank you very much!