Mac OSX Tiger printing to Windows XP Pro

My mum's computer has a Canon i550 attached to it and we are trying to make it so I can print directly to it from my intel iMac G5 running Tiger.

However, it just doesn't seem to work.

She has Zone Alarm (Free version) running and not windows firewall.

We have followed many tutorials all over the internet and none of them seem to work. I have installed drivers for the printer on my mac and when zone alarm is disabled, can detect the printer. However, from Microsoft word and print. Mac says that it has printed but nothing comes out the printer.

Computers are connected together through a router. PC to router via cable and iMac via wireless.

It has worked only once.

Need desperate help with this matter.

Thanks.