You might try checking your htaccess and php ini and see how much memory you have reserved. the tmp is a sql temporay storage area while doing sorting or some other routine which it needs to save the process while executing. If another process caused that sort or action to run out of space (or memory) then it could cause that error.
in your htaccess check for this command
php_value memory_limit (on a shared server i have ours set at 100M)
in your php ini file check for this command
memory_limit (on a shared server i have ours set at 100M)
you can set those as you like, since your on a ded server you have more flexibility with the settings so you can actually go larger im sure if you want to.
what did you change or did anything happen before this began to occure, this just not happen by itself, something had to change.
also on a different note.. when you post errors never post the full location, you just gave a kazillion people your cpanel login username.. noone ever needs to know that so you should have done it this way.
itFile:/home/xxxxxx/domains/xxxxxxx/public_html/ow_core/database.php
if we need to know your information a team member will ask, so never post your site name or username in an error message in public, notice that i xxxxx them out.. thats how you should do it to be safer.
