I completely uninstalled DW (ugh again), reinstalled, tried reinstalling the extension and same result. I downloaded the extension again from the WA site and tried installing that with same result. I decided I would try to re-install the earlier version of SA pro that I had which was 1.0.4. It installed just fine. I tried to install 1.0.7 over the earlier version, no change... it's still 1.0.4. Seems like an extension problem, doesn't it?
postscript: One additional observation that I don't know if it adds much. When the 1.0.7 appears to be installing, no boxes ever come up like the one for accepting the license agreement or asking if I want to do "Yes (or No) to all"