What do you mean never got it to work? Have you tried contacting their support? I just tried it and it worked just dandy for me.
I did contact their support via Chat and was told that neither Windows 8 nor IE 10 is on their compatibility list. Webex's meeting manager won't run on Windows 8 in Chrome or IE 10. It isn't like Cisco didn't know that this was coming. Very disappointing.
Hrm it's working for me. There must be something it doesn't like about your machine. At this point it's not a surprise since technically Windows 8 hasn't been officially released. Give them a little while after it's released to the public and they'll release a new version is my guess.
I am running RTM from Technet as well. Did you upgrade your windows 7 machine or do a fresh install? I did a totally fresh installation for mine. In any case give them some time. Software at my office hasn't been fully tested with RTM yet either. It takes time man.