Please change function
file: opengoo\application\views\reporting\total_task_times.php
This code:
<?php echo strtoupper(lang("total")) . ": " . DateTimeValue::FormatTimeDiff(new DateTimeValue(0), new DateTimeValue($sumTime * 60), "hm", 60) ?>
Change to:
<?php echo mb_strtoupper(lang("total"),"utf-8") . ": " . DateTimeValue::FormatTimeDiff(new DateTimeValue(0), new DateTimeValue($sumTime * 60), "hm", 60) ?>