Problem about Copy project

Fixed.

Thanks gerg35. You were almost there, and your analysis was correct.

To fix completely :
- sort array $activities before copying (then copy is in the good order), but sort must preserve keys (use uasort)
- then same issue with milestones : as they are copied after activities, order is not correct (they are alway after activities) : I had to implement array of object that can be of different classes, and adapt sort functionality.

Then it works !

Where can I configure the timeout to increase the value?

in php.ini,
max_execution_time = 300
or in the php code, for instance in copyProjctTo.php
set_time_limit(300);

It seems to be a little long time to take more than 30 seconds to copy the project, what do you think about?

Yes, it seems quite long... but all depends on your server capacity.
I should have a try...