All my clients are getting the "Error establishing a database connection" while clicking on the SitePad icon in cPanel. Also not sure how this is related to "WordPress" as indicated in the error message. Please see the attached screenshot.
Going to an account that never used SiteMush/Sitepad I got a too many redirects page. After visiting my own account that I had connected to sitemush before I now also get the 'Error establishing a database connection' on both my account and the customers account, exactly the same as SKGOLD has posted.