Hi Michael,
This is not an issue with Adobe Customization Wizard. This occurred probably because you are installing both the versions of the wizard on the same system.
We read the following registry to find the path of 'adobe_prtk.exe' :
"HKLM\Software\Microsoft\Windows\CurrentVersion\App Paths\InstallWizard.exe\Path"
It seems that either you have installed/repaired version10 after 11 so that this path has been updated.
It can be solved if you repair Customization Wizard XI.
Thanks,
Vinod