Line 1541 of source/class.wpdatatable.php contains
$tempFileName = ‘tempfile’ . $this->getWpId() . ‘.’ . $format;
this is then used by file_put_contents(…) without any regard to the current directory which, on my host happens to be /wp-admin which (GoDaddy) unfortunately (or resonably) restricts writes to. Unfortunately this makes wpDataTables fail when fetching files. Incorporating the temporary dir in the path would be an easy fix. For example:
$tempFileName = sys_get_temp_dir() . “/“ . ‘tempfile’ . $this->getWpId() . ‘.’ . $format;
Is a quick and resonably fix that doesn’t affect anything else.