Well I dont have to put 777 (775) on my Piwik tmp folder and I have done exactly everything I have stated in this thread to get it working. So there must be something you have missed. Did you reload priveleges or restart mysql? The problem is in something with your MySQL install, perhaps hit up the CentOS forums maybe they put some special sauce layer in their package that is giving you issues.
Also make sure something like SELinux is not preventing this.
Also make sure something like SELinux is not preventing this.
