Extension Manager and DW CS5 on Windows 7
I resolved my issue of EM CS5 not launching extensions on DW CS5. The answer is Adobe Forums Technical Support live chat. Sign up for an account and an agent will ask to share your screen and trouble shoot from there. My issue with EM ultimately involved having an agent set up a Test user account then reinstalling DW and the 11.0 updater. With the DW install came a fresh EM that launched and did not have File > Install Extension grayed out. Adobe's support was excellent. Be patient, this took me about 10 hours over several days and four or five agents but worth the effort.