This is the third post asking the same question. Multiple posts asking the same question will not get you the answer any sooner. The reason that you are not getting many responses is because most people are using newer versions of QTP. A simple Google search for flex 3 installation brings back 5,960,000 results or you could contact Adobe directly. You also asked if Flex 3 works with QTP 9.1. Contact HP, I'm certain that someone there would give you the answer you are seeking.