Database Error on some posts

Hey,

Yesterday i started getting the database error, “Error establishing a database connection”. But i am not getting this error on every page or post, its happening on some but not all. It wont let me log into the dashboard also. When i try to access the dashboard i get asked to repair the database, but it doesn’t seem to be working.

I have checked my wp-config.php file and everything seems to be correct. I have also tried removing some plugins, but that didnt work either.

My site is: http://techunfolding.com/site

Any help would be great. Thanks.