error in wordpress MU 3.0.1

When I activated the plugin, I have a Fatal Error:

Warning: mysql_result() [function.mysql-result]: Unable to jump to row 0 on MySQL result index 506 in /home/educa/public_html/wp-content/plugins/event-calendar-scheduler/codebase/dhtmlxSchedulerConfigurator.php on line 34

Fatal error: Call to a member function children() on a non-object in /home/educa/public_html/wp-content/plugins/event-calendar-scheduler/codebase/dhtmlxSchedulerConfigurator.php on line 85

any idea?.
Thanks.

Which version of php you are using?

Latest version works correctly with wordpress mu locally, so problem can be caused by some specific version|configuration of php or mysql in your case.

php version is 5.2.14

mysql version is 5.0.91