1st .... go to your WoW in program files then
click on interface this is in your computer.
2nd.... rename your current AddOns file to
AddOnss then create a new file named AddOns then when promted to download click Browse and got to your AddOns
and download it there.
3rd.... now you will need to unzip it for it to work
4th.... sign into your WoW and on the bottom left side of the screen
you should see Addons you will need to click on it to activate it and then it should work
click on this link to get the latest version, its currently 07/20/2008.
This will help you locate anything related to your quests and those
members of your group as well who also have questhelper downloaded.
click on this link to get the latest version to help in your instance runs.