Git commits in Moodle 1.9.18 by David Mudrak

commit 516878be1ec8696e26668b54ada1335fa0f666b1
Author: David Mudrak <david@moodle.com>
Date:   Fri, 06 Apr 2012 17:22:18 +0800
Tag:    v1.9.18

MDL-24403 Fixing the print_error() calls to use the existing string