Trying to install the trial version of Extension Builder 2.1 on windows 7 64bits,
I'm stopped by the msi app that is not go true the last step of install...
Saying that it can't install Extension Builder 2.1 because Extension Builder 2.1 is not installed !
Don't now what to do whit this.
Moving this discussion to the Creative Suite Extension Builder forum.
I finally succeded in installing Extension Builder 2.1.
I followed the advices from that forum topic http://forums.adobe.com/thread/1245836
and installed manually Flash Builder 4.6 before.
The first try failed. After cleaning of the registry for "Extension Builder" items, the installation succeded.