Software Deployment

hey guys, me again ;-)

here's another problem i have since yesterday afternoon.

i have packaged 7-zip which works fine. but when uninstalling, i want to change back the zip extension to the default that was there before it was changed by my msi.

i have a reg import to put every thing back as it was before the installation but it works only when distributed with an admin account logged to the computer. if the logged on user is not admin, like 99% of my customers, the zip extension is not set back so if i double-click a zip file, windows ask me what program to open with that file.

why is it working as admin but not as user? and it's not related to rights, because my deployment tool works with local system account.

thanks!