Did you call support?
Can't help but feel that if this were as simple as CS6 vs W8, we would be buried in complaints.
I did call support. Disabling the firewall succeeded on one computer. On the other two failed activations (both with Windows 8), nothing worked and the support folks had no answer. This product just is not compatible with Windows 8 without some workaround that no one seems to know.
I suspect there aren't many Windows 8 users
Are you using a volume licences or retail lincense.
For retail license the SN will only be activated in two systems.
Also are you getting any error .
if you are getting any error refer the below link :
Out-of-the-box installations all failed.
Installation failure and activation failure are entirely different issues. Very likely if the installation failed, you wouldn't have the opportunity to attempt an activation.
I've used Win 8 Pro for several months. Never had a Win 8 issue with Dreamweaver CS6, or any other Adobe product.