"The RPG Maker 2003 Runtime Package is not present or not registered." error

[Xathia Vastar]

Someone has been having trouble playing a my RM2k3 game, and I'm not sure why. I've included all of the RTP with the game when I packaged it, the user uninstalled/reinstalled the game multiple times but they are still getting an error that says: "The RPG Maker 2003 Runtime Package is not present or not registered." They are using Windows Vista operating system.
Can someone tell me what this means and how to fix it? Thanks in advance.

[Xathia Vastar]

Thank you! That worked!