Win7 has some added security features, which is a good thing in the fight against malware. But it does mean one needs Administration Privileges to install certain software. From what I understand this restriction is a Window's preference and some users are running with reduced settings to avoid it. This may or may not be a good thing, depending on how comfortable a user is managing Windows.
Here are the step by step instructions you should use...
a) Uninstall RV-7
Run the uninstall script:
Start > All Programs > BayTower > VANS-RV7 > Uninstall > Uninstall_RV7_v01-06-08
b) Reinstall RV-7 using admin privileges:
Right-click on your Flight1 RV-7 installer and select "Run as administrator"
Use the Click Here to Reinstall option.
You'll need to refer to your Flight1 email for your key file and password.
Your password is also available here: www.flight1.com lostPassWord
And yes, I agree adding a warning to the installer is a good idea. It would help avoid this issue.
Let me know if this works, there's another step we can take if not.