gloriousmonster.blogspot.com/2009/06/fixing-entsso-failure-on-windows-vista.html

Could not create SSOSQL. To fix the problem, reinstall SSO or try 'regasm SSOSQL.dll' from a Visual Studio command prompt.

Error Code: 0x80131700



It turns out this error told me everything I needed to know -- except the location of SSOSQL.dll. Took me a little digging, but I found it here:



C:\Program Files\Common Files\Enterprise Single Sign-On\SSOSQL.dll



So, navigating to that folder in the Visual Studio Commmand prompt and running 'regasm SSOSQL.dll' fixed it right up.