After some head scratching, I decided to troubleshoot this myself.
I generated logs, and found this:
MSI (s) (90:E8) [01:06:17:257]: Doing action: Set_DEVENV10PATHX86
Action start 1:06:17: Set_DEVENV10PATHX86.
MSI (s) (90:E8) [01:06:17:257]: PROPERTY CHANGE: Modifying DEVENV10PATHX86 property. Its current value is 'default'. Its new value: 'c:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\'.
Action ended 1:06:17: Set_DEVENV10PATHX86. Return value 1.
MSI (s) (90:E8) [01:06:17:257]: Skipping action: Set_DEVENV10PATHX64 (condition is false)
MSI (s) (90:E8) [01:06:17:257]: Doing action: Action1
What I ended up doing is this:
msiexec /package AMDgDEBugger-VisualStudioExtension-6.1.262-x64_signed.msi /
LVX amd5.log DEVENV10PATHX86="c:\Program Files (x86)\Microsoft Visual Studio 10.
0\Common7\IDE\"
That didn't work, same "default" error listed above.
I then tried this:
msiexec /package AMDgDEBugger-VisualStudioExtension-6.1.262-x64_signed.msi /
LVX amd5.log DEVENV10PATHX86="c:\Program Files (x86)\Microsoft Visual Studio 10.
0\Common7\IDE\" DEVENV10PATHX64="c:\Program Files (x86)\Microsoft Visual Studio
10.0\Common7\IDE\"
Eureka, that finally worked!
So, looks like whomever made the installer goofed... please fix for next time.