Author: Yevhenii Vlasenko
MDL-24403 Adding a missing error string
http://git.moodle.org/gw?p=moodle.git;a=commit;h=cf81547d49d7bd6c72e3199b262129fa2567d8e6
http://github.com/moodle/moodle/commit/cf81547d49d7bd6c72e3199b262129fa2567d8e6
+ 1.9 en [zipfileserror,error]