Playing DoW online with brother

[NecronLady]

I bought Dawn Of War: The Complete Collection long ago but I didn't play any game online, only skirmish or LAN with my brother (which is legal I think, as we didn't play game online), but recently I started playing online because of my friend. My brother wanted to play too.
He bought new CDs so he can play online with us. He uninstalled DC and installed it again with new CD and new CD key. He also used new codes for DoW and WA to unlock other five races following this guide (as I did before to save space, but with my codes).
But when he enters the online room when I'm already there, I get kicked with message that someone else used my CD key. Same for him when I connect again. But we use different CDs and different CD keys, and we cannot play together online with other people.
Please post solution as soon as you can.

Thank you.

[Slow_Runner]

Moved to DoW Tech Assistance. Sounds like you might have an old CD-key bouncing around in the registry somewhere.

[TBS]

Check the registry (the guide you linked details how) and confirm that the CD keys are different on the two machines.

[NecronLady]

Thanks to both of you for help, everything works fine now.