Updated Creative Suite CS5 to CS6 the other day. Installed on two computers (27" iMac i7 Oct 2009, and 2008 MacBook Pro 15"), everything worked fine. Ran the updates that Adobe Application Manager said were available. Worked fine on my laptop, but kept getting errors on my iMac. I had to go into terminal and give the installer sudo permissions to get it to run on the iMac, but it finally went. After updating, Dreamweaver no longer opens on my iMac (still works fine on my old MacBook Pro). It only bounces once in the doc - no splash screen, no opportunity to report a crash. I deleted preferences and cache to no avail. I then uninstalled Dreamweaver (using the installer, with remove preferences checked) and reinstalled it without running the update - it still won't open.
Well, I always seem to come up with questions that stump the crowd and have to figure these things out for myself in the end, which I did.
I logged in as root user (any alternative administrator account would work), and succesfully opened dreamweaver. I then copied all the preferences and support files to the main hard drive, where I retrieved them when I logged back into my user account. I then transferred those files to their respective places in the Library and Dreamweaver is now working again.