Just throwing this out there: have you asked on the Poser 11 Official Technical forum yet? Because users of pose5 11 may be able to answer you definitively. Just a thought.
I used Poser 11 before Poser 12 and it ran on my previous Windows version as well as now on Win10, but I assume you need it from someone who *right now* runs Win 7 and Poser 11 together.