Yea, active hub SHOULD mean powered HUB - I use "should" because with so much designs and sometimes, pseudo-designs, You can never be sure. anyway, in 99% powered hubs, You will also get power on line connected to N900 - not so much possibility for manufacturers to limit that, would require very complicated circuit and probably conflict with device power-on-port discovery - so N900 should charge.

It's indeed strange that Your devices stop working when You try to use charger script. Maybe Your power supply can't provide enough current to power both keyboard/mouse and N900? Its strange a little, because mouse and keyboard don't need much power.