Duration time issue


I have a problem with dhtmlxGantt component.
My XML (incomplete, tasks are deeper than first level):

<task id="13779"> <name>General task</name> <est>2012,9,11</est> <duration>616</duration> <percentcompleted>50</percentcompleted> <predecessortasks/> <childtasks> <task id="21279"> <name>Subtask 1</name> <est>2012,11,26</est> <duration>8</duration> <percentcompleted>0</percentcompleted> <predecessortasks/> <childtasks/> </task> </childtasks> </task>

Gantt said “DATA_ERROR Increase duration of parent task (13779) or reduce EST of child task (21279) or reduce duration of child task (21279)”. Why this error occur? Duration is calculated well, I think.

Please help, thank you in advance.

I forgot important thing:
When I added to “13779” task one more hour - it works, but i don’t want to do that. How to solve the problem?

I am also having the same issue and its kinda irritating. Will try and apply your fix for now however maybe with version 2 this will be sorted.